Embryology - User contributions [en-gb]

User:Z3330986

2012-10-16T23:30:50Z

Z3330986: /* Lab Attendance */

==Lab Attendance==
Lab 1
--[[User:Z3330986|Z3330986]] 11:49, 25 July 2012 (EST)

Lab 2
--[[User:Z3330986|Z3330986]] 10:25, 1 August 2012 (EST)

Lab 3
--[[User:Z3330986|Z3330986]] 10:33, 8 August 2012 (EST)

Lab 4
--[[User:Z3330986|Z3330986]] 10:21, 15 August 2012 (EST)

Lab 5
--[[User:Z3330986|Z3330986]] 10:27, 22 August 2012 (EST)

Lab 6
--[[User:Z3330986|Z3330986]] 11:55, 29 August 2012 (EST)

Lab 7
--[[User:Z3330986|Z3330986]] 10:54, 12 September 2012 (EST)

Lab 8
--[[User:Z3330986|Z3330986]] 10:31, 19 September 2012 (EST)

Lab 9
--[[User:Z3330986|Z3330986]] 10:10, 26 September 2012 (EST)

Lab 11
--[[User:Z3330986|Z3330986]] 10:10, 10 October 2012 (EST)

Lab 12
--[[User:Z3330986|Z3330986]] 10:24, 17 October 2012 (EST)

==Individual Assessment==
===Lab 1===

1) As with many medical terms, ''in vitro'' is derived from Latin, translating to "in glass." It is so named, as early experiments involving tissue cultures outside of the specimen (as opposed to ''in vivo'', inside the body) were undertaken in glass containers. In Vitro Fertilization was developed by Robert G. Edwards. He was awarded the Nobel prize in 2010 in the field of medicine and physiology for his work. A link to the Nobel prize web page can be found here:[[http://www.nobelprize.org]]

2) '''Sperm counts and sperm sex ratio in male infertility patients'''[[http://www.ncbi.nlm.nih.gov.wwwproxy0.library.unsw.edu.au/pubmed/22842703]]

In this study, the sex chromosomes and sperm count of infertile men were analysed in order to determine whether infertility plays a role in the determination offspring gender. Infertility is a fairly arbitrary categorization though for the purposes for this experiment, it was taken to mean couples who had greater than or equal to two recurrent pregnancy losses or two failed IVF treatments. The subsequent results found that in men with a low sperm concentration, semen volume and total motile sperm count, there was a significantly lower proprortion of the Y-bearing sperm. Thus there is a direct link between spermatogenesis and sex ratio.

The precise mechanisms for a diminished Y-bearing proportion of sperm is unclear. It is suggested that perhaps societal stresses or individual wants and needs may play a role in the genetic makeup of sperm. Biologically, it is reasoned that an infertile man will produce less male heirs so as to minimise the chance that his offspring may encounter the same problems.

===Lab 2===

[[Image:Mouse oocytes in vitro.png|thumb|Mouse oocytes in vitro]]

In order for successful implantation to occur, estrogen controlled proliferation of the uterine epithelium must be attenuated by the hormone progesterone. Previously the mechanisms of attenuation were not well understood however recent study has shown the helix-loop-helix protein, Hand2, plays an integral role in
suppressing estrogen-driven growth of uterine epithelium. It does this by stopping the induction of Fibroblast growth factors (FGF) which are responsible for maintaining estrogen mediated growth of the epithelium. [1]

From a clinical perspective it may also direct research to improve treatments which target over-proliferative disorders such as endometriosis and endometrial cancer. Particularly endometriosis, which currently resists progesterone targeted medications.

'''Reference'''

1. The Antiproliferative Action of Progesterone in Uterine Epithelium Is Mediated by Hand2
Quanxi Li, Athilakshmi Kannan, Francesco J. DeMayo, John P. Lydon, Paul S. Cooke, Hiroyuki Yamagishi, Deepak Srivastava, Milan K. Bagchi, and Indrani C. Bagchi
Science 18 February 2011: 331 (6019), 912-916. [DOI:10.1126/science.1197454]

===Lab 3===

1) Gestational age refers to the age of the foetus/embryo beginning at the first day of the mother's last menstrual cycle. In contrast the post-fertilisation age, as its name infers, begins at the time of fertilisation of the oocyte.

2) Somites mainly generate: Skeletal muscle and dermis (from the dermomyotome) as well as intervertebral discs and vertebral bodies (from the sclerotome)

'''Histology'''

*Skeletal muscle - Contains densely packed fibers called myofibrils. These are cylindrical, long and multinucleated fibres with nuclei residing peripherally. Each myofibril is composed of the proteins actin and myosin (referred to collectively as myofilaments). Skeletal muscle can be divided into either red fibres or white fibres:

::*Red fibers are named due to the presence of myoglobin, an oxygen transporting protein, analagous to haemoglobin in the blood. They contain many mitochondria and are responsible for slow twitch contractile movements.

::*White fibers are larger with less myoglobin and mitochondria. These represent fast twitch fibers

*Dermis - Bilaminar structure composed of Papillary layer and Reticular layer.

::* Papillary layer - Superficial layer interdigitating with the dermis. Composed of loose connective tissue with thin type III collagen fibers. Also contains macrophages, fibroblasts and mast cells along with capillary loops which function in thermoregulation.

::* Reticular layer - Deepest layer containing intermingling thick elastic fibers and collagen fibers.

*Intervertebral disc - made up of fibrocartilage. The matrix contains cartilage cells, enclosed within lacunae which align in pairs or short rows between bundles of type I collagen fibers.

===Lab 4===

There are two main types of invasive prenatal diagnostic techniques

* Amniocentesis - Amniotic fluid is taken and analysed between 14th and 18th week of pregnancy. It is used primarily to test for chromosomal defects such as Down Syndrome or fetal infections. It may be used to test for maternal hypertension (''preeclampsia'') by looking for protein biomarkers.

* Chorionic villi sampling - Cells from the chorionic villus are taken between 10th and 12th week gestational age. It is used to test for chromosomal abnormalities such as Down syndrome or cystic fibrosis.

2) '''Systemic administration of a novel human umbilical cord mesenchymal stem cells population accelerates the resolution of acute liver injury'''

Traditionally when liver hepatocytes are damaged during end-stage liver disease, the only option has been transplantation. New research conducted by Burra et al (2011) however has focused upon using human umbilical cord mesenchymal stem cells (UCMSCs) as a form of regenerative treatment. In this study, UCMSCs were induced to form hepatic cell types through the use of growth factors ''in vitro'', whilst ECM components derived from surgical specimens were used as a basis of support for these cells. These cells were then transplanted into carbon tetrachloride infected mouse livers which had undergone more than 40% necrosis of its total parenchymal tissue.

When UCMSCs were recruited within liver tissue, it was found that inflammation had been reduced through the regulation of pro-inflammatory cytokines and reduction of infiltrate. Furthermore there was a higher proportion of Kupffer cells (liver macrophages) identified through histological analysis compared to untreated liver tissue. This finding lends weight to the idea that UCMSCs accelerate liver cell recovery by attenuating the inflammation process.

Another therapeutic advantage of UCMSCs was the increase of catalase activity. The amount of catalase enzyme present in UCMSC treated liver tissue was markedly increased around Day 5, resulting in enhanced elimination of reactive oxygen species (ROS) which would otherwise cause oxidative damage to hepatocytes.

===Lab 7===
1a) A satellite cell, also referred to as a muscle stem cell, is a quiescent cell which functions to repair and or form new muscle fibres.

b) Activation of satellite cells occurs primarily during muscle injury. When a muscle fibre is damaged through physical injury, the satellite cells become mytotically active and fuse with the existing muscle fibres to repair the damaged tissue. Similarly in chronic diseases such as Duchenne’s muscular dystrophy, satellite cells are activated and differentiate into new myotubes in order to replace dying muscle fibres.

2) Damage to the motor nerve, classified as a motor neuron lesion, manifests in flaccid paralysis in the affected individual. This is a result of the loss of electrical signalling from the motor nuclei of the spinal cord to the muscle spindle. Consequently the individual presents with reduced muscle tone (hypotonia) and muscle wasting (atrophy). On a cellular level, muscle fibre size decreases whilst there is a fibre type shift from type I to type II fibres. This represents a down regulation of the slow myosin heavy chain (MHC) isoform and up regulation of fast MHC isoforms. [1]

'''References'''

1. Scelsi, R (2001). Skeletal Muscle Pathology after Spinal Cord Injury: Our 20 YearExperience and Results on Skeletal Muscle Changes in Paraplegics,Related to Functional Rehabilitation. Basic Appl Myol 11 (2): 75-85,

==Peer assessment==

===Vision===

Use of historic images was good. This is a main point of difference between this project and the rest. They are however not very well integrated into the project page, they feel as if they have simply been pasted there for the sake of inclusion. Perhaps an explanation of their significance could be included as well as how these drawings have lead to more refined understandings of specific structures. The Research History section is also quite interesting although it is very brief and could be improved if it were presented in a more visually appealing manner such as in a colour table.

The development structure and function section is excellent. The text is easy to follow and the student drawn images demonstrate a clear understanding of the processes as well as giving the reader the opportunity to better visualise the different stages of development. Another image which could be included would perhaps be a histological picture (as opposed to a diagram) of the different cell layers of the retina ie. The photoreceptor layer, inner nuclear layer etc.
The current research section needs further refinement. I see no reason to simply list some current research articles except for point of reference. What needs to be done is explain how current research has changed or challenged traditional views/concepts. A brief summary of each article listed in this section is also warranted.

All images and relevant ideas appear to be appropriately cited and referenced. Image formatting on the whole is quite good although I think those included in the introduction need to be altered as they skew the text, making the section look awkward and a bit difficult to read.

===Somatosensory===

The introduction is ok, there is an imbalance between text and pictures. Particularly there is a sentence which reads “The following picture shows the general organization of the somatosensory system” however there is no picture. Also in terms of sentence structure, there are four sentences in a row which begin with “the somatosensory system...” or “the system...” Try to alternate how different ideas are expressed as at the moment the paragraph reads as a disjunct of ideas.

As a whole the page’s visual appeal needs ameliorating. There is far too much text and only two pictures, one of which is very large and appears to be compensating for a lack of smaller relevant diagrams within the body of each section. Having said this, the neural development section was very well done. It was detailed without being verbose and showed it was well researched. The hand drawn diagram is excellent. The cell biology part was also very well written and well structured however again, it simply need some visuals to aid in some descriptions of molecular processes.
There appears not to be a continuous referencing style on the page. The introduction has in-text referencing whilst the rest of the page contains endnotes. A minor problem which could be fixed easily, though quite important nonetheless.

===Olfaction===

The project page was exceptional, there is a fine combination of text and images and the images are well integrated with the presented information. I particularly like the inclusion of a hand drawn histological section embedded within the table of historical findings. Perhaps this could also be done in the next table about the developmental timeline. As it stands, this table, while detailed in its wording may be difficult to understand as there are no diagrams to show the differentiation in visual terms, from week to week.

The clinical features, anatomy, and pathohophysiology were excellent. There is not much more to say. All of the diagrams were properly cited with correct copyright information. The CT scan was also interesting to look at.

One aspect that hasn’t been touched on is future research. The current research section was very detailed and explained the significance of each new finding however as is the nature of research, there are always gaps left in our understanding or further questions that need to be resolved as a result of new information. A brief section on this would give the project more depth as it would show a level of critique rather than simply the presentation of fact.

===Abnormal vision===

From the outset the page presents as well structured, particularly the introduction which provides the reader with a clear understanding of the purpose and content of the page. The following content is detailed and well researched with equal emphasis place upon each section. It appears that the page was contributed to equally by each member.

The image comparing the fundus between albinism and a normal eye is too small. The formatting is easily fixed by including the pixel size in the image insert directory. To find out how to do this refer to the wiki reference card we were given, or online.
One minor structuring problem comes from the “ocular manifestations” sections. When it says “Major ocular disorders can be split into two separate sections based on the way in which they originated,” please list the two separate classifications immediately in bullet form. i.e.
*Genetic
*Environmental

By the time the section about the environmental origins arises, I forgot what it was referring back to and thus I had to scroll back up to deduce it was the second part of the ocular manifestations heading. Apart from this there are no other major faults of the project. All images are cited and copyright information clearly recognisable.

===Hearing===

I liked the tone of the introduction, it was light hearted and enjoyable to read, especially the image of the dog in the beginning which I thought was great. It also instructed the reader about the content of the page, thereby having a good balance between being engaging and informative.

The development section is extremely detailed, which is good in terms of showing a breadth of research and understanding however this needs to be offset with a greater deal of visual information. The subsections detailing the middle and outer ear are in need of some images showing the pharyngeal arches and their morphological changes from week to week. It would also be nice to see either some hand drawn images or computer drawn diagrams included somewhere in the page just for some variation. Towards the end of the page in the Abnormal hearing and the technological sections it tends to become very text heavy and need some image content. For example a photo of a cochlear implant would be useful.

There is some variation in the referencing style in Technology section with references appearing at the end of the section. It would be better to incorporate these references into the text as endnotes as they appear in the other sections of the project. Furthermore some of the tables are incomplete and require the addition of images. The image column in the structural malformations of the ear is empty. I’m not sure if there was a formatting problem or otherwise, though this need to be rectified.

Overall the page is very well written with an appropriate style aimed at students of the same level or higher. The glossary is extensive as is the reference list, showing an obvious depth of research.

User:Z3330986

2012-10-16T23:24:42Z

Z3330986: /* Lab Attendance */

==Lab Attendance==
Lab 1
--[[User:Z3330986|Z3330986]] 11:49, 25 July 2012 (EST)

Lab 2
--[[User:Z3330986|Z3330986]] 10:25, 1 August 2012 (EST)

Lab 3
--[[User:Z3330986|Z3330986]] 10:33, 8 August 2012 (EST)

Lab 4
--[[User:Z3330986|Z3330986]] 10:21, 15 August 2012 (EST)

Lab 5
--[[User:Z3330986|Z3330986]] 10:27, 22 August 2012 (EST)

Lab 6
--[[User:Z3330986|Z3330986]] 11:55, 29 August 2012 (EST)

Lab 7
--[[User:Z3330986|Z3330986]] 10:54, 12 September 2012 (EST)

Lab 8
--[[User:Z3330986|Z3330986]] 10:31, 19 September 2012 (EST)

Lab 9
--[[User:Z3330986|Z3330986]] 10:10, 26 September 2012 (EST)

Lab 11
--[[User:Z3330986|Z3330986]] 10:10, 10 October 2012 (EST)
Lab 12
--[[User:Z3330986|Z3330986]] 10:24, 17 October 2012 (EST)

==Individual Assessment==
===Lab 1===

1) As with many medical terms, ''in vitro'' is derived from Latin, translating to "in glass." It is so named, as early experiments involving tissue cultures outside of the specimen (as opposed to ''in vivo'', inside the body) were undertaken in glass containers. In Vitro Fertilization was developed by Robert G. Edwards. He was awarded the Nobel prize in 2010 in the field of medicine and physiology for his work. A link to the Nobel prize web page can be found here:[[http://www.nobelprize.org]]

2) '''Sperm counts and sperm sex ratio in male infertility patients'''[[http://www.ncbi.nlm.nih.gov.wwwproxy0.library.unsw.edu.au/pubmed/22842703]]

In this study, the sex chromosomes and sperm count of infertile men were analysed in order to determine whether infertility plays a role in the determination offspring gender. Infertility is a fairly arbitrary categorization though for the purposes for this experiment, it was taken to mean couples who had greater than or equal to two recurrent pregnancy losses or two failed IVF treatments. The subsequent results found that in men with a low sperm concentration, semen volume and total motile sperm count, there was a significantly lower proprortion of the Y-bearing sperm. Thus there is a direct link between spermatogenesis and sex ratio.

The precise mechanisms for a diminished Y-bearing proportion of sperm is unclear. It is suggested that perhaps societal stresses or individual wants and needs may play a role in the genetic makeup of sperm. Biologically, it is reasoned that an infertile man will produce less male heirs so as to minimise the chance that his offspring may encounter the same problems.

===Lab 2===

[[Image:Mouse oocytes in vitro.png|thumb|Mouse oocytes in vitro]]

In order for successful implantation to occur, estrogen controlled proliferation of the uterine epithelium must be attenuated by the hormone progesterone. Previously the mechanisms of attenuation were not well understood however recent study has shown the helix-loop-helix protein, Hand2, plays an integral role in
suppressing estrogen-driven growth of uterine epithelium. It does this by stopping the induction of Fibroblast growth factors (FGF) which are responsible for maintaining estrogen mediated growth of the epithelium. [1]

From a clinical perspective it may also direct research to improve treatments which target over-proliferative disorders such as endometriosis and endometrial cancer. Particularly endometriosis, which currently resists progesterone targeted medications.

'''Reference'''

1. The Antiproliferative Action of Progesterone in Uterine Epithelium Is Mediated by Hand2
Quanxi Li, Athilakshmi Kannan, Francesco J. DeMayo, John P. Lydon, Paul S. Cooke, Hiroyuki Yamagishi, Deepak Srivastava, Milan K. Bagchi, and Indrani C. Bagchi
Science 18 February 2011: 331 (6019), 912-916. [DOI:10.1126/science.1197454]

===Lab 3===

1) Gestational age refers to the age of the foetus/embryo beginning at the first day of the mother's last menstrual cycle. In contrast the post-fertilisation age, as its name infers, begins at the time of fertilisation of the oocyte.

2) Somites mainly generate: Skeletal muscle and dermis (from the dermomyotome) as well as intervertebral discs and vertebral bodies (from the sclerotome)

'''Histology'''

*Skeletal muscle - Contains densely packed fibers called myofibrils. These are cylindrical, long and multinucleated fibres with nuclei residing peripherally. Each myofibril is composed of the proteins actin and myosin (referred to collectively as myofilaments). Skeletal muscle can be divided into either red fibres or white fibres:

::*Red fibers are named due to the presence of myoglobin, an oxygen transporting protein, analagous to haemoglobin in the blood. They contain many mitochondria and are responsible for slow twitch contractile movements.

::*White fibers are larger with less myoglobin and mitochondria. These represent fast twitch fibers

*Dermis - Bilaminar structure composed of Papillary layer and Reticular layer.

::* Papillary layer - Superficial layer interdigitating with the dermis. Composed of loose connective tissue with thin type III collagen fibers. Also contains macrophages, fibroblasts and mast cells along with capillary loops which function in thermoregulation.

::* Reticular layer - Deepest layer containing intermingling thick elastic fibers and collagen fibers.

*Intervertebral disc - made up of fibrocartilage. The matrix contains cartilage cells, enclosed within lacunae which align in pairs or short rows between bundles of type I collagen fibers.

===Lab 4===

There are two main types of invasive prenatal diagnostic techniques

* Amniocentesis - Amniotic fluid is taken and analysed between 14th and 18th week of pregnancy. It is used primarily to test for chromosomal defects such as Down Syndrome or fetal infections. It may be used to test for maternal hypertension (''preeclampsia'') by looking for protein biomarkers.

* Chorionic villi sampling - Cells from the chorionic villus are taken between 10th and 12th week gestational age. It is used to test for chromosomal abnormalities such as Down syndrome or cystic fibrosis.

2) '''Systemic administration of a novel human umbilical cord mesenchymal stem cells population accelerates the resolution of acute liver injury'''

Traditionally when liver hepatocytes are damaged during end-stage liver disease, the only option has been transplantation. New research conducted by Burra et al (2011) however has focused upon using human umbilical cord mesenchymal stem cells (UCMSCs) as a form of regenerative treatment. In this study, UCMSCs were induced to form hepatic cell types through the use of growth factors ''in vitro'', whilst ECM components derived from surgical specimens were used as a basis of support for these cells. These cells were then transplanted into carbon tetrachloride infected mouse livers which had undergone more than 40% necrosis of its total parenchymal tissue.

When UCMSCs were recruited within liver tissue, it was found that inflammation had been reduced through the regulation of pro-inflammatory cytokines and reduction of infiltrate. Furthermore there was a higher proportion of Kupffer cells (liver macrophages) identified through histological analysis compared to untreated liver tissue. This finding lends weight to the idea that UCMSCs accelerate liver cell recovery by attenuating the inflammation process.

Another therapeutic advantage of UCMSCs was the increase of catalase activity. The amount of catalase enzyme present in UCMSC treated liver tissue was markedly increased around Day 5, resulting in enhanced elimination of reactive oxygen species (ROS) which would otherwise cause oxidative damage to hepatocytes.

===Lab 7===
1a) A satellite cell, also referred to as a muscle stem cell, is a quiescent cell which functions to repair and or form new muscle fibres.

b) Activation of satellite cells occurs primarily during muscle injury. When a muscle fibre is damaged through physical injury, the satellite cells become mytotically active and fuse with the existing muscle fibres to repair the damaged tissue. Similarly in chronic diseases such as Duchenne’s muscular dystrophy, satellite cells are activated and differentiate into new myotubes in order to replace dying muscle fibres.

2) Damage to the motor nerve, classified as a motor neuron lesion, manifests in flaccid paralysis in the affected individual. This is a result of the loss of electrical signalling from the motor nuclei of the spinal cord to the muscle spindle. Consequently the individual presents with reduced muscle tone (hypotonia) and muscle wasting (atrophy). On a cellular level, muscle fibre size decreases whilst there is a fibre type shift from type I to type II fibres. This represents a down regulation of the slow myosin heavy chain (MHC) isoform and up regulation of fast MHC isoforms. [1]

'''References'''

1. Scelsi, R (2001). Skeletal Muscle Pathology after Spinal Cord Injury: Our 20 YearExperience and Results on Skeletal Muscle Changes in Paraplegics,Related to Functional Rehabilitation. Basic Appl Myol 11 (2): 75-85,

==Peer assessment==

===Vision===

Use of historic images was good. This is a main point of difference between this project and the rest. They are however not very well integrated into the project page, they feel as if they have simply been pasted there for the sake of inclusion. Perhaps an explanation of their significance could be included as well as how these drawings have lead to more refined understandings of specific structures. The Research History section is also quite interesting although it is very brief and could be improved if it were presented in a more visually appealing manner such as in a colour table.

The development structure and function section is excellent. The text is easy to follow and the student drawn images demonstrate a clear understanding of the processes as well as giving the reader the opportunity to better visualise the different stages of development. Another image which could be included would perhaps be a histological picture (as opposed to a diagram) of the different cell layers of the retina ie. The photoreceptor layer, inner nuclear layer etc.
The current research section needs further refinement. I see no reason to simply list some current research articles except for point of reference. What needs to be done is explain how current research has changed or challenged traditional views/concepts. A brief summary of each article listed in this section is also warranted.

All images and relevant ideas appear to be appropriately cited and referenced. Image formatting on the whole is quite good although I think those included in the introduction need to be altered as they skew the text, making the section look awkward and a bit difficult to read.

===Somatosensory===

The introduction is ok, there is an imbalance between text and pictures. Particularly there is a sentence which reads “The following picture shows the general organization of the somatosensory system” however there is no picture. Also in terms of sentence structure, there are four sentences in a row which begin with “the somatosensory system...” or “the system...” Try to alternate how different ideas are expressed as at the moment the paragraph reads as a disjunct of ideas.

As a whole the page’s visual appeal needs ameliorating. There is far too much text and only two pictures, one of which is very large and appears to be compensating for a lack of smaller relevant diagrams within the body of each section. Having said this, the neural development section was very well done. It was detailed without being verbose and showed it was well researched. The hand drawn diagram is excellent. The cell biology part was also very well written and well structured however again, it simply need some visuals to aid in some descriptions of molecular processes.
There appears not to be a continuous referencing style on the page. The introduction has in-text referencing whilst the rest of the page contains endnotes. A minor problem which could be fixed easily, though quite important nonetheless.

===Olfaction===

The project page was exceptional, there is a fine combination of text and images and the images are well integrated with the presented information. I particularly like the inclusion of a hand drawn histological section embedded within the table of historical findings. Perhaps this could also be done in the next table about the developmental timeline. As it stands, this table, while detailed in its wording may be difficult to understand as there are no diagrams to show the differentiation in visual terms, from week to week.

The clinical features, anatomy, and pathohophysiology were excellent. There is not much more to say. All of the diagrams were properly cited with correct copyright information. The CT scan was also interesting to look at.

One aspect that hasn’t been touched on is future research. The current research section was very detailed and explained the significance of each new finding however as is the nature of research, there are always gaps left in our understanding or further questions that need to be resolved as a result of new information. A brief section on this would give the project more depth as it would show a level of critique rather than simply the presentation of fact.

===Abnormal vision===

From the outset the page presents as well structured, particularly the introduction which provides the reader with a clear understanding of the purpose and content of the page. The following content is detailed and well researched with equal emphasis place upon each section. It appears that the page was contributed to equally by each member.

The image comparing the fundus between albinism and a normal eye is too small. The formatting is easily fixed by including the pixel size in the image insert directory. To find out how to do this refer to the wiki reference card we were given, or online.
One minor structuring problem comes from the “ocular manifestations” sections. When it says “Major ocular disorders can be split into two separate sections based on the way in which they originated,” please list the two separate classifications immediately in bullet form. i.e.
*Genetic
*Environmental

By the time the section about the environmental origins arises, I forgot what it was referring back to and thus I had to scroll back up to deduce it was the second part of the ocular manifestations heading. Apart from this there are no other major faults of the project. All images are cited and copyright information clearly recognisable.

===Hearing===

I liked the tone of the introduction, it was light hearted and enjoyable to read, especially the image of the dog in the beginning which I thought was great. It also instructed the reader about the content of the page, thereby having a good balance between being engaging and informative.

The development section is extremely detailed, which is good in terms of showing a breadth of research and understanding however this needs to be offset with a greater deal of visual information. The subsections detailing the middle and outer ear are in need of some images showing the pharyngeal arches and their morphological changes from week to week. It would also be nice to see either some hand drawn images or computer drawn diagrams included somewhere in the page just for some variation. Towards the end of the page in the Abnormal hearing and the technological sections it tends to become very text heavy and need some image content. For example a photo of a cochlear implant would be useful.

There is some variation in the referencing style in Technology section with references appearing at the end of the section. It would be better to incorporate these references into the text as endnotes as they appear in the other sections of the project. Furthermore some of the tables are incomplete and require the addition of images. The image column in the structural malformations of the ear is empty. I’m not sure if there was a formatting problem or otherwise, though this need to be rectified.

Overall the page is very well written with an appropriate style aimed at students of the same level or higher. The glossary is extensive as is the reference list, showing an obvious depth of research.

User:Z3330986

2012-10-09T23:10:51Z

Z3330986: /* Lab Attendance */

==Lab Attendance==
Lab 1
--[[User:Z3330986|Z3330986]] 11:49, 25 July 2012 (EST)

Lab 2
--[[User:Z3330986|Z3330986]] 10:25, 1 August 2012 (EST)

Lab 3
--[[User:Z3330986|Z3330986]] 10:33, 8 August 2012 (EST)

Lab 4
--[[User:Z3330986|Z3330986]] 10:21, 15 August 2012 (EST)

Lab 5
--[[User:Z3330986|Z3330986]] 10:27, 22 August 2012 (EST)

Lab 6
--[[User:Z3330986|Z3330986]] 11:55, 29 August 2012 (EST)

Lab 7
--[[User:Z3330986|Z3330986]] 10:54, 12 September 2012 (EST)

Lab 8
--[[User:Z3330986|Z3330986]] 10:31, 19 September 2012 (EST)

Lab 9
--[[User:Z3330986|Z3330986]] 10:10, 26 September 2012 (EST)

Lab 11
--[[User:Z3330986|Z3330986]] 10:10, 10 October 2012 (EST)

==Individual Assessment==
===Lab 1===

1) As with many medical terms, ''in vitro'' is derived from Latin, translating to "in glass." It is so named, as early experiments involving tissue cultures outside of the specimen (as opposed to ''in vivo'', inside the body) were undertaken in glass containers. In Vitro Fertilization was developed by Robert G. Edwards. He was awarded the Nobel prize in 2010 in the field of medicine and physiology for his work. A link to the Nobel prize web page can be found here:[[http://www.nobelprize.org]]

2) '''Sperm counts and sperm sex ratio in male infertility patients'''[[http://www.ncbi.nlm.nih.gov.wwwproxy0.library.unsw.edu.au/pubmed/22842703]]

In this study, the sex chromosomes and sperm count of infertile men were analysed in order to determine whether infertility plays a role in the determination offspring gender. Infertility is a fairly arbitrary categorization though for the purposes for this experiment, it was taken to mean couples who had greater than or equal to two recurrent pregnancy losses or two failed IVF treatments. The subsequent results found that in men with a low sperm concentration, semen volume and total motile sperm count, there was a significantly lower proprortion of the Y-bearing sperm. Thus there is a direct link between spermatogenesis and sex ratio.

The precise mechanisms for a diminished Y-bearing proportion of sperm is unclear. It is suggested that perhaps societal stresses or individual wants and needs may play a role in the genetic makeup of sperm. Biologically, it is reasoned that an infertile man will produce less male heirs so as to minimise the chance that his offspring may encounter the same problems.

===Lab 2===

[[Image:Mouse oocytes in vitro.png|thumb|Mouse oocytes in vitro]]

In order for successful implantation to occur, estrogen controlled proliferation of the uterine epithelium must be attenuated by the hormone progesterone. Previously the mechanisms of attenuation were not well understood however recent study has shown the helix-loop-helix protein, Hand2, plays an integral role in
suppressing estrogen-driven growth of uterine epithelium. It does this by stopping the induction of Fibroblast growth factors (FGF) which are responsible for maintaining estrogen mediated growth of the epithelium. [1]

From a clinical perspective it may also direct research to improve treatments which target over-proliferative disorders such as endometriosis and endometrial cancer. Particularly endometriosis, which currently resists progesterone targeted medications.

'''Reference'''

1. The Antiproliferative Action of Progesterone in Uterine Epithelium Is Mediated by Hand2
Quanxi Li, Athilakshmi Kannan, Francesco J. DeMayo, John P. Lydon, Paul S. Cooke, Hiroyuki Yamagishi, Deepak Srivastava, Milan K. Bagchi, and Indrani C. Bagchi
Science 18 February 2011: 331 (6019), 912-916. [DOI:10.1126/science.1197454]

===Lab 3===

1) Gestational age refers to the age of the foetus/embryo beginning at the first day of the mother's last menstrual cycle. In contrast the post-fertilisation age, as its name infers, begins at the time of fertilisation of the oocyte.

2) Somites mainly generate: Skeletal muscle and dermis (from the dermomyotome) as well as intervertebral discs and vertebral bodies (from the sclerotome)

'''Histology'''

*Skeletal muscle - Contains densely packed fibers called myofibrils. These are cylindrical, long and multinucleated fibres with nuclei residing peripherally. Each myofibril is composed of the proteins actin and myosin (referred to collectively as myofilaments). Skeletal muscle can be divided into either red fibres or white fibres:

::*Red fibers are named due to the presence of myoglobin, an oxygen transporting protein, analagous to haemoglobin in the blood. They contain many mitochondria and are responsible for slow twitch contractile movements.

::*White fibers are larger with less myoglobin and mitochondria. These represent fast twitch fibers

*Dermis - Bilaminar structure composed of Papillary layer and Reticular layer.

::* Papillary layer - Superficial layer interdigitating with the dermis. Composed of loose connective tissue with thin type III collagen fibers. Also contains macrophages, fibroblasts and mast cells along with capillary loops which function in thermoregulation.

::* Reticular layer - Deepest layer containing intermingling thick elastic fibers and collagen fibers.

*Intervertebral disc - made up of fibrocartilage. The matrix contains cartilage cells, enclosed within lacunae which align in pairs or short rows between bundles of type I collagen fibers.

===Lab 4===

There are two main types of invasive prenatal diagnostic techniques

* Amniocentesis - Amniotic fluid is taken and analysed between 14th and 18th week of pregnancy. It is used primarily to test for chromosomal defects such as Down Syndrome or fetal infections. It may be used to test for maternal hypertension (''preeclampsia'') by looking for protein biomarkers.

* Chorionic villi sampling - Cells from the chorionic villus are taken between 10th and 12th week gestational age. It is used to test for chromosomal abnormalities such as Down syndrome or cystic fibrosis.

2) '''Systemic administration of a novel human umbilical cord mesenchymal stem cells population accelerates the resolution of acute liver injury'''

Traditionally when liver hepatocytes are damaged during end-stage liver disease, the only option has been transplantation. New research conducted by Burra et al (2011) however has focused upon using human umbilical cord mesenchymal stem cells (UCMSCs) as a form of regenerative treatment. In this study, UCMSCs were induced to form hepatic cell types through the use of growth factors ''in vitro'', whilst ECM components derived from surgical specimens were used as a basis of support for these cells. These cells were then transplanted into carbon tetrachloride infected mouse livers which had undergone more than 40% necrosis of its total parenchymal tissue.

When UCMSCs were recruited within liver tissue, it was found that inflammation had been reduced through the regulation of pro-inflammatory cytokines and reduction of infiltrate. Furthermore there was a higher proportion of Kupffer cells (liver macrophages) identified through histological analysis compared to untreated liver tissue. This finding lends weight to the idea that UCMSCs accelerate liver cell recovery by attenuating the inflammation process.

Another therapeutic advantage of UCMSCs was the increase of catalase activity. The amount of catalase enzyme present in UCMSC treated liver tissue was markedly increased around Day 5, resulting in enhanced elimination of reactive oxygen species (ROS) which would otherwise cause oxidative damage to hepatocytes.

===Lab 7===
1a) A satellite cell, also referred to as a muscle stem cell, is a quiescent cell which functions to repair and or form new muscle fibres.

b) Activation of satellite cells occurs primarily during muscle injury. When a muscle fibre is damaged through physical injury, the satellite cells become mytotically active and fuse with the existing muscle fibres to repair the damaged tissue. Similarly in chronic diseases such as Duchenne’s muscular dystrophy, satellite cells are activated and differentiate into new myotubes in order to replace dying muscle fibres.

2) Damage to the motor nerve, classified as a motor neuron lesion, manifests in flaccid paralysis in the affected individual. This is a result of the loss of electrical signalling from the motor nuclei of the spinal cord to the muscle spindle. Consequently the individual presents with reduced muscle tone (hypotonia) and muscle wasting (atrophy). On a cellular level, muscle fibre size decreases whilst there is a fibre type shift from type I to type II fibres. This represents a down regulation of the slow myosin heavy chain (MHC) isoform and up regulation of fast MHC isoforms. [1]

'''References'''

1. Scelsi, R (2001). Skeletal Muscle Pathology after Spinal Cord Injury: Our 20 YearExperience and Results on Skeletal Muscle Changes in Paraplegics,Related to Functional Rehabilitation. Basic Appl Myol 11 (2): 75-85,

==Peer assessment==

===Vision===

Use of historic images was good. This is a main point of difference between this project and the rest. They are however not very well integrated into the project page, they feel as if they have simply been pasted there for the sake of inclusion. Perhaps an explanation of their significance could be included as well as how these drawings have lead to more refined understandings of specific structures. The Research History section is also quite interesting although it is very brief and could be improved if it were presented in a more visually appealing manner such as in a colour table.

The development structure and function section is excellent. The text is easy to follow and the student drawn images demonstrate a clear understanding of the processes as well as giving the reader the opportunity to better visualise the different stages of development. Another image which could be included would perhaps be a histological picture (as opposed to a diagram) of the different cell layers of the retina ie. The photoreceptor layer, inner nuclear layer etc.
The current research section needs further refinement. I see no reason to simply list some current research articles except for point of reference. What needs to be done is explain how current research has changed or challenged traditional views/concepts. A brief summary of each article listed in this section is also warranted.

All images and relevant ideas appear to be appropriately cited and referenced. Image formatting on the whole is quite good although I think those included in the introduction need to be altered as they skew the text, making the section look awkward and a bit difficult to read.

===Somatosensory===

The introduction is ok, there is an imbalance between text and pictures. Particularly there is a sentence which reads “The following picture shows the general organization of the somatosensory system” however there is no picture. Also in terms of sentence structure, there are four sentences in a row which begin with “the somatosensory system...” or “the system...” Try to alternate how different ideas are expressed as at the moment the paragraph reads as a disjunct of ideas.

As a whole the page’s visual appeal needs ameliorating. There is far too much text and only two pictures, one of which is very large and appears to be compensating for a lack of smaller relevant diagrams within the body of each section. Having said this, the neural development section was very well done. It was detailed without being verbose and showed it was well researched. The hand drawn diagram is excellent. The cell biology part was also very well written and well structured however again, it simply need some visuals to aid in some descriptions of molecular processes.
There appears not to be a continuous referencing style on the page. The introduction has in-text referencing whilst the rest of the page contains endnotes. A minor problem which could be fixed easily, though quite important nonetheless.

===Olfaction===

The project page was exceptional, there is a fine combination of text and images and the images are well integrated with the presented information. I particularly like the inclusion of a hand drawn histological section embedded within the table of historical findings. Perhaps this could also be done in the next table about the developmental timeline. As it stands, this table, while detailed in its wording may be difficult to understand as there are no diagrams to show the differentiation in visual terms, from week to week.

The clinical features, anatomy, and pathohophysiology were excellent. There is not much more to say. All of the diagrams were properly cited with correct copyright information. The CT scan was also interesting to look at.

One aspect that hasn’t been touched on is future research. The current research section was very detailed and explained the significance of each new finding however as is the nature of research, there are always gaps left in our understanding or further questions that need to be resolved as a result of new information. A brief section on this would give the project more depth as it would show a level of critique rather than simply the presentation of fact.

===Abnormal vision===

From the outset the page presents as well structured, particularly the introduction which provides the reader with a clear understanding of the purpose and content of the page. The following content is detailed and well researched with equal emphasis place upon each section. It appears that the page was contributed to equally by each member.

The image comparing the fundus between albinism and a normal eye is too small. The formatting is easily fixed by including the pixel size in the image insert directory. To find out how to do this refer to the wiki reference card we were given, or online.
One minor structuring problem comes from the “ocular manifestations” sections. When it says “Major ocular disorders can be split into two separate sections based on the way in which they originated,” please list the two separate classifications immediately in bullet form. i.e.
*Genetic
*Environmental

By the time the section about the environmental origins arises, I forgot what it was referring back to and thus I had to scroll back up to deduce it was the second part of the ocular manifestations heading. Apart from this there are no other major faults of the project. All images are cited and copyright information clearly recognisable.

===Hearing===

I liked the tone of the introduction, it was light hearted and enjoyable to read, especially the image of the dog in the beginning which I thought was great. It also instructed the reader about the content of the page, thereby having a good balance between being engaging and informative.

The development section is extremely detailed, which is good in terms of showing a breadth of research and understanding however this needs to be offset with a greater deal of visual information. The subsections detailing the middle and outer ear are in need of some images showing the pharyngeal arches and their morphological changes from week to week. It would also be nice to see either some hand drawn images or computer drawn diagrams included somewhere in the page just for some variation. Towards the end of the page in the Abnormal hearing and the technological sections it tends to become very text heavy and need some image content. For example a photo of a cochlear implant would be useful.

There is some variation in the referencing style in Technology section with references appearing at the end of the section. It would be better to incorporate these references into the text as endnotes as they appear in the other sections of the project. Furthermore some of the tables are incomplete and require the addition of images. The image column in the structural malformations of the ear is empty. I’m not sure if there was a formatting problem or otherwise, though this need to be rectified.

Overall the page is very well written with an appropriate style aimed at students of the same level or higher. The glossary is extensive as is the reference list, showing an obvious depth of research.

File:Taste qualities.gif

2012-10-03T01:03:13Z

Z3330986: /* Copyright information */

==Taste qualities==
Taste qualities, the taste receptors that detect them, and examples
of natural stimuli. Five recognized taste qualities—sweet, sour,
bitter, salty, and umami—are detected by taste buds. Bitter taste is thought
to protect against ingesting poisons, many of which taste bitter. Sweet
taste signals sugars and carbohydrates. Umami taste is elicited by l-amino
acids and nucleotides. Salty taste is generated mainly by Na+ and sour
taste potently by organic acids. Evidence is mounting that fat may also
be detected by taste buds via dedicated receptors. The names of taste receptors
and cartoons depicting their transmembrane topology are shown
outside the perimeter. Bitter is transduced by G protein–coupled receptors
similar to Class I GPCRs (with short extracellular N termini). In contrast,
sweet and umami are detected by dimers of Class III GPCRs (with long
N termini that form a globular extracellular ligand-binding domain). One of
the receptors for Na+ salts is a cation channel composed of three subunits,
each with two transmembrane domains. Membrane receptors for sour and
fat are as yet uncertain.<ref name=PMID20696704><pubmed>20696704</pubmed></ref>

==Copyright information==
© 2010 Chaudhari and Roper This article is distributed under the terms of an Attribution–
Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication
date (see http://www.rupress.org/terms). After six months it is available under a
Creative Commons License (Attribution–Noncommercial–Share Alike 3.0 Unported license,
as described at http://creativecommons.org/licenses/by-nc-sa/3.0/).

{{Template:Student Image}}

==References==
1. Nirupa Chaudhari, Stephen D Roper The cell biology of taste. J. Cell Biol.: 2010, 190(3);285-96 PMID:20696704

2012 Group Project 3

2012-10-03T01:00:28Z

Z3330986: /* Gustatory System */

=Taste Development=

You are out to dinner and your meal arrives in front of you, the aromas and the presentation of your food strikes you immediately. Half way through, the waiter returns and asks “How does your meal taste?” The answer is not as simple as one might think. Why does the meal taste pleasant? How do we experience different tastes? In the following page, we aim to discern how exactly one would answer these questions by looking at the embryological development of the taste system from week to week.

Taste is a complex sensory system and its precise workings are to this day not fully understood. What makes it so complicated is the interaction between the structure of tongue and taste buds and how this contributes to the representation of taste qualities (salty, bitter, sweet, sour and umami) in the brain. We will also look at some current research on animal models being undertaken to evaluate the role of specific genes in the development of sensory structures. By looking at the taste system’s genetic basis, we now have a greater understanding of the abnormalities that may occur during development and a direction to pursue in future research to attempt to fill in the gaps of scientific knowledge.

==Adult Tongue and Taste Buds – Structure and Function==

'''Structure'''

The tongue is located on the floor of the oral cavity, It is a muscular structure with sensory units crowning. The tongue is divided into an anterior two thirds and a posterior one third. These regions are divided by a V-shaped groove at the back of the tongue (sulcus terminalis). The anterior two thirds of the tongue is covered by stratified squamous epithelium, It contains a roughened surface and has projections called papillae that vary in shape and number.

[http://www.webmd.com/oral-health/picture-of-the-tongue]

''''The image below is a simplistic diagram of the surface of the tongue showing the locations of the different papillae and other important features'''

{|
| [[Image:Drawing of Tongue.png|centre|500px]]

[[File:Taste_pathway.jpg|right|thumb|200px|Simplistic Pathway of Taste]]

'''Papillae'''

There are 4 types of papillae on the tongue.
The most numerous papillae are the filiform papillae, which function to provide a surface that aids in holding food on the tongue during chewing but do not contain taste buds. The larger, less numerous fungiform papillae which contain taste buds, as do foliate papillae. Circumvallate papillae form a wide V at the sulcus terminalis also containing taste bus. There are no papillae or taste buds located on the posterior third of the tongue, having mucosal folds and the lingual tonsils instead.[http://www.tutorvista.com/content/biology/biology-iv/nervous-coordination/tongue-structure.php#parts-of-tongue]

[[File:Papillae.jpg|Left|thumb|200px|Close up of Human Tongue Papillae]]

[[File:Fungiformpapillae.jpg|left|thumb|200px|Fungiform Papillae]]

[[File:Circumvallatepapillae.jpg |left|thumb|200px|Circumvallate Papillae]]

[[File:Filiformpapillae.jpg|left|200px|thumb|Foliate Papillae]]

'''Function'''

The Tongue has muscular and sensory functions, muscular functions include swallowing and speech where as sensory function involves taste. This section will focus on the sensory functions of the tongue.
The functional unit of the taste bud is a taste cell, there are between 50 and 100 taste cells in each taste bud these taste cells represent all 5 different tastes. Historically is was believed that different areas of the tongue were responsible for different taste sensations although this has since been disregarded.[http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/W/Welcome.html] The papillae contain taste buds which are connected to the oral cavity via a taste pore, the function of the taste bud is to transmit a chemical signal from the oral cavity to a taste cell, this chemical signal is the converted into an electrical impulse and delivered to the brain via nerve fibres for interpretation. [http://www.cf.ac.uk/biosi/staffinfo/jacob/teaching/sensory/taste.html]

[[File:Taste_bud_1.jpg|right|thumb|200px|Cross section of a taste bud unit|centre|Cross section of a taste bud unit]]

'''Link Between Taste and Smell'''

The pathways of smell and taste are very similar (chemosensation). Pathways both involve the conversion of a dissolved chemical stimulus transformed into a electrical impulse for interpretation by the brain.
Taste and smell overlap when humans experience flavour, flavour involves an interaction of taste, smell, texture and temperature, where taste is only a portion of this interaction. when the brain interprets a flavour, contribution from other senses has a significant role in identification. In conclusion Taste and Smell in combination with other senses help develop a sensory interpretation called flavour.[http://www.entnet.org/HealthInformation/smellTaste.cfm]
[[File:Human smelling.jpg|500px|centre]]

==History of Discoveries==

{| cellpadding=5 style="border:1px solid #BBB"
|- bgcolor="#faecc8"
|''' Date'''|| '''Significant Discovery'''

|- bgcolor="#faf6ed"
|'''350BC'''
|| Aristotle writes about the basic tastes, sweet and bitter. He also notes that it can be modified by salty and acidic. <ref name="PMID22717400"><pubmed>22717400</pubmed></ref>

|- bgcolor="#faecc8"
|'''1901'''
|| D. Hanig publishes a paper describing taste sensitivity in different regions of the tongue.
''Interesting fact:'' The modern concept of a 'tongue map' is a misinterpretation of this study. <ref name="PMID22717400"/>

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''1908'''
|Kikunae Ikeda, a professor of the Tokyo Imperial University, discovered and identified the fifth basic taste: umami (savouriness), made palatable by glutamate. <ref><pubmed>12438213</pubmed></ref>
[http://chemse.oxfordjournals.org/content/27/9/847.long New Seasonings]

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''1931-32'''
| A chemist named Arthur Fox and his college noted that they had different sensitivities to the bitter tasting Phenylthiocarbamide (PTC).<ref>Blakeslee AF, Fox AL. Our different taste worlds. J Hered. 1932;23:97–107.</ref> Geneticists later confirm these findings, and discover that non-tasting is a recessive genetic trait. <ref><pubmed>17782493</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pubmed/17782493 Inherited taste deficiency]

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''1965'''
|Farbman's study of the developing taste but in rat fungiform papilla was significant in increasing our understanding of taste bud development. <ref><pubmed>14300090</pubmed></ref>
[http://www.sciencedirect.com/science/article/pii/0012160665900400 Electron microscope study of the developing taste bud in rat fungiform papilla.]

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''1992'''
|McLaughlin SK et al. discovery a taste cell-specific G-protein within the taste buds called Gustucon. This protein is later used to mark bitter, umami and sweet cells. <ref><pubmed>1608467 </pubmed></ref>
[http://www.nature.com/nature/journal/v357/n6379/abs/357563a0.html Gustducin is a taste-cell-specific G protein closely related to the transducins]

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''1995'''
|Barlow et al. experimented with Axolotl salamanders and concluded that taste buds from this species arise exclusively from epithelial tissue, "oropharyngeal [[#Glossary |'''epithelium''']]". <ref name="PMID17826760"><pubmed>17826760</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pubmed/17826760 Embryonic origin of gustatory cranial sensory neurons]

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''1996'''
| Witt M and Reutter K of the Technical University Dresden in Germany, carried out a transmission electron microscopy study to investigate the embryonic and fetal development of Human taste buds. Their results suggest an "at least dual function of embryonic/fetal taste buds", including non-gustatory, paracrine functions prior to the 14th week and gustatory after the 14th week. <ref name="PMID8955790"><pubmed>8955790</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pubmed/8955790 Embryonic and early fetal development of human taste buds: a transmission electron microscopical study]

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''2000'''
|Chandrashekar, J. et al. discover the first taste sonsors, the T2R bitter taste receptors. <ref><pubmed>10761935</pubmed></ref>
[http://www.sciencedirect.com/science/article/pii/S0092867400807060 T2Rs Function as Bitter Taste Receptors]

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''2001'''
|Nelson, G. et al. discover the sweet receptor: a combination of T1R2 and T1R3. <ref><pubmed>11509186</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pubmed/11509186?dopt=Abstract&holding=npg Mammalian sweet taste receptors.]

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''2002'''
|Nelson G. et al. discover the amino acid (umami) taste receptor: a combination of T1R1 and T1R3 identified. <ref><pubmed>11894099</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pubmed/11894099?dopt=Abstract&holding=npg An amino-acid taste receptor]

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''2005'''
|Dyer, J. et al. discover sweet taste receptors in the GI tract. <ref><pubmed>17855558</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1986582/ Sweet taste signaling in the gut]

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''2006'''
|Huang, A. L et al. discover cells for sour taste, identified by PKD2L1 (a polycystic kidney disease-like ion channel). <ref><pubmed>16929298</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1571047/ The Cells and Logic for Mammalian Sour Taste detection]

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''2007'''
|Harlow DE, Barlow LA of the University of Colorado Denver Health Sciences Center provide evidence of the "embryonic origin of gustatory cranial sensory neurons". <ref name="PMID17826760"/>
[http://www.ncbi.nlm.nih.gov/pubmed/17826760 Embryonic origin of gustatory cranial sensory neurons.]

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''2009'''
|A study by Hevezi P et al, presents "the first comprehensive characterization of gene expression in primate taste buds", as opposed to previous studies which focused on rodents. <ref><pubmed>19636377</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pubmed/19636377 Genome-wide analysis of gene expression in primate taste buds reveals links to diverse processes]

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''2010'''
|Chandrashekar, J. et al. identify epithelial sodium channel (ENaC) as the sodium-salt taste receptor. <ref><pubmed>20107438</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pubmed/20107438?dopt=Abstract&holding=npg The cells and peripheral representation of sodium taste in mice]
|}

== Human Weekly Development - Two Prominent Studies ==
Martin Witt and Klaus Reutter of the University of Tubingen in Germany published two prominent studies regarding developing taste buds in humans. Their first study in 1996 was a transmission electron microscopical (TEM) study of the taste bud primordium and its morphological changes during the 8th-15th postovulatory week. Their next study in 1997 built on their previous findings by using Scanning Electron Microscopy (SEM) to observe the development of gustatory [[#Glossary |'''papillae''']] during postovulatory weeks 6-15.

The findings of these two studies are summarized in the table below. The figures provided relate to the images on their respective research papers.

# [http://onlinelibrary.wiley.com/doi/10.1002/(SICI)1097-0185(199612)246:4%3C507::AID-AR10%3E3.0.CO;2-S/pdf Embryonic and early fetal development of human taste buds: a transmission electron microscopical study, 1996]
# [http://chemse.oxfordjournals.org/content/22/6/601.long Scanning electron microscopical studies of developing gustatory papillae in humans, 1997]

===Timeline of Developmental Processes of Human Taste Buds===
{| cellpadding=5 style="border:1px solid #BBB"
|- bgcolor="#89CFF0"
|'''Postovulatory Week'''||'''Description'''

|- bgcolor="#BCD4E6"
|'''Week 6''' ||
The surface of the developing tongue is covered by nearly flat epithelium (1997, Figure 1). The first gustatory papillae of the tongue appear in the caudal mid-line near the foramen caecum and the first circumvallate papilla develops on the dorsal mid-line. <ref name="PMID9455607"><pubmed>9455607</pubmed></ref>

|- bgcolor="#89CFF0"
| '''Weeks 6 to 7'''||
Nerve fibers approach the basal lamina of lingual epithelium. At this stage the lingual epithelium consists of two to three cell layers and there is not yet any sign of cell specializations indicating early taste bud formation. <ref name=PMID8955790/>

|- bgcolor="#BCD4E6"
| '''Week 7 '''||
A series of irregular epithelial swellings in the anterior part and marginal parts of the tongue indicate early forming fungiform papillae. Furthermore, a V-like lane is observed anterior to the [[#Glossary |'''sulcus terminalis''']], which represents a smooth surface for developing circumvallate papillae (1997, Figure 2). Witt M et al observe that these circumvallate papillae are larger than the developing fungiform papillae of the same age, later noting that the fungiform papillae tend to increase in size over the 8-15th weeks of gestation, whilst the size of vallate papillae tend to remain constant during this period. <ref name=PMID9455607/>

|- bgcolor="#89CFF0"
| ''' Week 8 ''' ||
* The taste bud primordium are still differentiated, elongated epithelial cells, resting on a slightly developed core of young dermal papilla.
* The lingual epithelium shows first signs of taste bud development as nerve fibers coming from the dermal papilla penetrate the epithelial basal lamina and form synapses with taste bud progenitor cells (1996, Figure 1). These synapses demonstrate the neuronal connection between the taste bud primordium and the central nervous system, reaching a maximum around the 12th to 13th week. However, it is important to note that at this time these cells are still poorly differentiated, elongated epithelial cells.
* Ciliated cells also appear around the 8th week, however the significance of these cells which are scattered randomly across the lingual surface remains unclear. <ref name=PMID8955790/>

|- bgcolor="#BCD4E6"
|''' Week 9''' ||
By this stage, although a taste pore is not present, the surface of circumvallate papillae usually contains a taste pit partly filled with microvillus-like processes from the underlying taste bud cells (1997, Figure 10). <ref name=PMID9455607/>

|- bgcolor="#89CFF0"
|''' Weeks 10-11''' ||
At this stage, the lingual epithelium compromises of about four cell layers, and the first shallow grooves above the taste bud primordium are developed. Fungiform papillae appear on the lateral margins and the tip of the tongue, containing taste bud primordial that display the first signs of a primitive pore formation (1996, Figure 6). <ref name=PMID8955790/>

|- bgcolor="#BCD4E6"
|''' Week 12 ''' ||
Taste bud cells are more clearly differentiated into epithelial cell types II and III. <ref name=PMID8955790/>

|- bgcolor="#89CFF0"
|''' Weeks 12-13 ''' ||
At this stage the taste bud primordial are all located on the top of dermal papillae. There is also maximum synapses between cells and afferent nerve fibers, which intermingle with each other to form a plexus-like structure (1996, Figure 6a). <ref name=PMID8955790/>

|- bgcolor="#BCD4E6"
|''' Weeks 14 -15 ''' ||
The shape and size of the taste buds primordial begins to resemble those of adult taste buds (1996, Figure 9). By the 14th week the taste pores develop as the taste pits are filled by microvilli, and bubble like vesicles indicate the secretory activity of these cells (1996, Figure 10). However, the taste buds only achieve a fully developed function in week 15 of gestation with the development of type I cells to produce the mucous material in the taste pit. <ref name=PMID8955790/>
|}

==Abnormalities==

It should be mentioned that gustatory abnormalities have not been widely researched. Most research conducted in this field has been conducted through animal testing on mice and this is the basis of information provided below.

===Knocking out P2X Receptors===

[[File:Image of taste being evoked by visualising ATP release.jpeg|Left|thumb|200px|Evoking taste - ATP release in tongue]]

In Huang, 2008 this team used the release of the [[#Glossary |'''ectoderm''']], ATP (adenosine triphosphate) as a quantitative measurement of gustatory sensation and taste. This was done by using a comparison of wild type (WT) and double knockout (DKO) mice. P2X receptors, P2X2 and P2X3 were knocked out in the DKO mice. The premise of this article was that knocking out P2X receptors reduces transmitter secretion of ATP in taste buds, therefore they cannot taste.

It should be noted that the taste buds in DKO are functional, but are not stimulated by the administration of tastants.

The transmission of release of ATP is secretion through gap junction hemichannels (pannexin 1 gap junction).

When both P2X2 and P2X3 are knocked out, no taste is elicited. However they found that if either P2X2 OR P2X3 was knocked out there was a taste response. So the inference made from this is that if one of the two receptors from the P2X family was knocked out there still can have taste response. The WT mice showed significant stimulation by tastants whereas DKO had little to no stimulation of ATP release.<ref><pubmed>21940456</pubmed></ref>

===FGF signalling and genes===

Sprouty, or ''Srpy'', genes have been related to regulating the development of circumvallate papillae (CVP). The CVP are large dome shaped papillae, which form a 'V' just in front of the terminal sulcus.

By knocking out ''Spry'' genes using mice which had ''Spry1'' and ''Spry2'' knocked out showed that the number of CVP doubled. However, when Fibroblast [[#Glossary |'''Growth Factor''']] gene ("Fgf10") was absent, the number of CVP was significantly reduced, if not completely absent. The correlation between ''Spry1/2'' and ''Fgf10'' is that ''Spry1/2'' antagonizes "Fgf10" to limit the size of the CVP progenitor placode. Exclusive expression of ''Fgf10'' in the [[#Glossary |'''mesenchyme''']] is necessary for the formation of CVP.

'''This image shows the CVP stained with H&E and scanned by Scanning Electron Microscope (SEM)'''
[[File:CVP of WT(top) and DKO(bottom) mice with H&E and SEM.png]]

'''This image shows the location of the CVP and the increased number in DKO mice by SEM'''
[[File:Mouse circumvallate papilla 01.jpg|300px]]

Taste buds develop from the mesenchyme but require local signalling to properly differentiate. Some signalling factors for proper development of taste buds besides FGF are: [[#Glossary |'''Sonic Hedgehog''']] (SHH), Bone Morphogenetic Proteins (BMPs), Epidermal Growth Factor (EGF).

Additionally, this proves that the anterior and posterior developments of the tongue are derived from embryonic tissues, where the anterior tongue is derived from the [[#Glossary |'''ectoderm''']] and the posterior tongue is derived from the [[#Glossary |'''endoderm''']]. Taste buds develop from the mesenchyme but require local signalling to properly differentiate. Some signalling factors for proper development of taste buds besides FGF are: Sonic Hedgehog (SHH), Bone Morphogenetic Proteins (BMPs), Epidermal Growth Factor (EGF).

As mentioned above, this article shows that the anterior and posterior developments of the tongue are derived from embryonic tissues, where the anterior tongue is derived front the ectoderm and the posterior tongue is derived from the endoderm. Secondly, FGF is required to regulate the growth of taste buds, while ''Spry'' genes limit the number of CVP. ''Fgf10''& ''Spry 1&2''work antagonistically through receptor tyrosine kinase (RTK)signalling.

However, the deletion of ''Spry2''led to the increase of CVPs it should be noted that they found that a significant decrease in number of fungiform papillae. In contrast, the absence of ''Fgf10'', while leading to the absence of CVPs lead to an increase in number and size of fungiform papillae. Therefore these genes have different effects on the anterior and posterior developing tongue and taste buds.<ref><pubmed>21655085</pubmed></ref>

==Gustatory System==

[[Image:Taste qualities.gif|thumb|The five basic tastes]]

Taste or more appropriately gustation, is a fundamental survival tool in animals as it directs the consumption of essential nutrients. The five tastes that exist within the human gustatory system: salty, sweet, sour, bitter and umami, all signify basic physiological requirements. Salty tastes denote the presence of Na+, an important ion involved in the transportation and retention of water across cell membranes. Sweetness is the recognition of carbohydrates, essential for maintaining optimal brain function and providing the basis for energy production in muscle tissue via ATP [[#Glossary |'''hydrolysis''']]. Similarly umami codes for the presence of L-amino acids, especially L-glutamate which is an integral component of protein synthesis.

These different modalities not only function to maintain the proper intake of nutrients within the body but also, by way of aversion, prohibit the consumption of undesired or poisonous materials. The bitter modality for example is generally regarded as displeasing to the human palate. It represents a high acid content which may be a result of foods which have become rotten or are inherently poisonous to the body.<ref name=PMID20696704><pubmed>20696704</pubmed></ref>

Research has historically limited itself to investigating the mechanisms of these five taste qualities though it must be noted many other modalities may exist. Of particular conjecture is the existence of fatty acid recognition. In the past the detection of fat in food has been attributed to somatosensory inputs <ref name=PMID20696704/> from the tongue, that is, the oily feel and texture of fat rather than its actual ‘taste’ allows the brain to encode for its presence. Further research is therefore required to elicit the precise mechanisms of fat detection.

===Cell Biology===

The five taste qualities are not all detected by the same type of receptor cell located within the taste bud. Like rods and cones in the eye which detect different wavelengths of light, there are specific types of receptors for different tastes. For example, sweet, umami and bitter are recognized by Type II G-protein coupled receptors, whereas sour is related to Type III presynaptic cells. <ref name=PMC2674259><pubmed>2674259</pubmed></ref> The cell type involved in salty taste transduction is unknown however it is known that sodium ions can enter the receptor cell membrane via ion channel permeation.

====Type II receptors====

When a bitter, sweet or umami ligand binds to a type II G-coupled receptor, a cascade of chemical reactions causes the release of Ca2+ which in turn mediates [[#Glossary |'''exocystosis''']] of ATP. The function of this ATP is threefold:

# Stimulates gustatory nerve afferents which project to gustatory nuclei in the spinal cord
# Excites Type III presynaptic nerve fibers to release serotonin. <ref name=PMC2674259><pubmed>2674259</pubmed></ref>
# Has a positive feedback effect on type II receptor cells, increasing the level of ATP production.

The role of serotonin is believed to be in the form of lateral inhibition <ref name=PMID20696704><pubmed>20696704</pubmed></ref>
i.e. when a bitter quality is recognized, adjacent receptors for sweetness are deactivated and thus the two tastes may be clearly differentiated. It also has a negative feedback effect on receptor cells, inhibiting umami, bitter and sweet taste transduction.

==Taste Map==
[[Image:Taste map.png|thumb|left|250px|Obsolete idea of the tongue map]]
The idea of a tongue map has disseminated through society for many years. This concept purports that different areas of the tongue are specialized to detect either sweet, salty, sour and bitter tastes. Recent research however has completely nullified such claims and suggests instead that different forms of taste are recognized all over the tongue as well as via the palate. Thus the term ''taste map'' has come to take on a new meaning and that is, the precise areas of taste modalities processing in areas of cortex and its subsequent neural inputs.

===Neural Pathways===

'''First order [[#Glossary |'''neuron''']]''' - From the receptors located in the taste buds, gustatory nerve afferents project to the ipsilateral rostral 1/3 of the nucleus tractus solitarius (NTS), located in the medulla. This rostral 1/3 is commonly referred to as the ''gustatory nucleus''.

The ''gustatory nucleus'' receives input from cranial nerves VII (''Facial n.''), IX (''Hypglossal n.''), and X (''Vagus n.'') via special visceral afferent (SVA) nerve fibers. A summary of their functions is as follows:

* ''Facial nerve n''. - carries taste information from the anterior 2/3 of the tongue.
* ''Hypoglossal n.'' - carries taste information from the posterior 1/3 of the tongue.
* ''Vagus n''. - carries taste information from the palate

'''Second order neurons''' - From the NTS second order neurons carry taste information to the Ventral posteromedial (VPM) nucleus in the thalamus.<ref name=PMID21885776/>

Copious scientific conjecture surrounds how each taste modality is transmitted to the brain. The ‘labelled-line’ hypothesis suggests that there are taste specific neurons which exclusively carry that taste modality to cortical areas. In analogous terms it can be viewed like the pipelines leading toward a house. Each pipeline carries its own utility, there is one for gas, another for water and finally for electricity with each terminating in slightly different areas of the house. In the same way, on the tongues there are different receptors for each taste which concurrently have individual nerve tracts leading to the primary gustatory cortex.

Contrapuntally there is electrophysiological evidence that single nerve afferents carry multiple modalities. These studies show one nerve afferent may have both a strong and a weak activation in response to a multiple taste stimuli.

===Cortical Areas===

[[Image:Primary gustatory cortex.png|thumb|Primary gustatory cortex]]

The location of the taste perception centers has been observed via functional magnetic resonance imaging (fMRI) studies. The primary taste cortex has been identified as being located in the anterior insula/frontal operculum (I/fO)<ref name=PMID22245354><pubmed>22245354</pubmed></ref>, with the secondary taste cortex in the caudolateral orbitofrontal cortex.<ref name=PMID21305668><pubmed>21305668</pubmed></ref> Within the insula there are further subdivisions related to each taste modality. Two photon calcium imaging research has outlined certain ’hot-spots’ of activation which are clearly delineated in relation to each taste. For example, the bitter modality is represented on the insula cortex approximately 1mm posterior to the middle cerebral artery whereas the sweet modality is represented 2.5mm rostrodorsal to the bitter field with no apparent overlap.<ref name=PMID21885776><pubmed>21885776</pubmed></ref> These findings lend weight to the idea that there is only one receptor for each taste quality.

It is interesting to note the relationship between taste and the reward centers of the brain. There is evidence of neural input to the ventral tegmental area (the origin of the mesolimbic dopaminergic reward pathway) and nucleus accumbens (involved in the conversion of motivation into physical action).<ref name=PMID21885776/> Neural connections such as this provide the foundations in explaining concepts such as flavour learning and preference. It may also give some insight into chronic problems such as food addiction and craving. As of yet however the gustatory neural network is not well understood and more research is required to elucidate the relationship between pleasure and taste sensation

===Neuronal Development===

The gustatory system must not be solely thought of as being comprised of simply the tongue and palate. The types of neurons which carry taste information to the brain are also pivotal in constructing the expression of taste qualities.

The two main gustatory neurons which develop are the geniculate ganglion and the petrosal ganglion. These are the visceral sensory ganglion of cranial nerves VII (Facial) and IX (Hypoglossal) respectively which carry taste information from the tongue to the nucleus tractus solitarius.<ref name=PMC2078608><pubmed>2078608</pubmed></ref> They arise at the posterior placodal region from the epibranchial placodes, a thickening of ectoderm. The first epibranchial placode gives rise to the geniculate ganglion and the second to the petrosal ganglion.<ref name=PMC1995452><pubmed>1995452</pubmed></ref>

The molecular basis for gustatory neuron formation is not completely understood though there are a number of transcription factors which are thought to play an important role in firstly, placode formation and secondly, neuron differentiation.

*Six1/2, Six1/5 and Eya – transcription factors which cause differentiation of epibranchial placodes into the petrosal and geniculate ganglion.
*Bone morphogenic Protein 7 (BMP7) – a signal arising from the pharyngeal pouch which is believed to induce epibranchial placode formation. May not be solely responsible for this process, current research has been inconclusive as to how it may work with other proteins of the same family.
*NGN2 - Following the initial differentiation of the placodes, further differentiation occurs to form neuroblasts. NGN2 causes the delamination and migration of these neuroblasts, which subsequently migrate and fuse to form neurons.<ref name=PMC1995452><pubmed>1995452</pubmed></ref>
*Phox2b – maintains the structural integrity of neurons. Knockout of these genes in mice causes marked atrophy of the petrosal and geniculate ganglia.

The neurons involved in the gustatory system are overproduced and thus in the embryonic stage, undergo programmed cell death (apoptosis). The total amount of neurons in the geniculate ganglion, appears to be quite stable over the embryonic stages. This suggests, unlike the petrosal ganglion, the levels of neuroblast proliferation and apoptosis are fairly similar. The factors which regulate these processes remains unclear. It is posited that neurotrophins BDNF, NT4/5 and NT3 may regulate neuronal survival<ref name=PMC3070660><pubmed>3070660</pubmed></ref> whilst also playing a part in axon growth from the sensory ganglion. More research is required to discern the exact individual functions of each of the neurotrophins.

==Current Research==

[[File:Mousetounge histologicalstain.jpg|right|thumb|200px|Image shows histological stains of a mice tongue showing dysplasia]]

We have an evolving understanding of Embryonic Taste development, through the use of state-of-the-art technology and research techniques we are able to make brilliant discoveries that continue to connect the dots of this amazing natural process of human development.
The majority of research in taste development is involving mice, these mammals show similar embryonic pathways to humans and research is performed in ethical and humane methods.

'''Synergistic relationships of Six Genes '''

In an animal study using mice by Suzuki Y, Ikeda K, Kawakami K.(2011) Firstly nominating "[[#Glossary |'''Six Genes''']]" as a major component in [[#Glossary |'''gustatory ''']] development, stating that deficiencies in certain Six genes (specifically Six1 & Six4) leads to poor development. Their research also highlights evidence of cooperative relationships between Six genes for normal advance. This experiment involved breeding mice containing exclusively Six1 and Six4 genes and examining the expression of these genes in papillae under high powered microscope observation. Understanding the role of certain genes along with the intrinsic relationships they hold is crucial for the ability to identify possible causes and correction of any abnormalities <ref><pubmed>21978088</pubmed></ref>

[[File:Highpowered_microscope.jpg|Left|thumb|200px|Image of a high powered microscope]]

'''Neural Crest responsibilities '''

Another Animal Study involving mice explores a new idea of [[#Glossary |'''Neural crest''']] (NC) contribution in taste development, specifically the development of papillae and taste buds. Liu HX, Komatsu Y, Mishina Y, Mistretta CM. (2012) suggest that Neural crest cells travel to the location of the tongue in early embryonic stages, gain epithelium phenotypes, multiply and then differentiate to eventually form taste papillae. The experiment involved the comparison of 2 different types of Cre line mice, which both express Cre gene in neural crest protocol, the different distribution patterns where observed in specific regions that NC is responsible for.<ref><pubmed>22659543</pubmed></ref>

'''Augmentation of Endoderm'''

In an animal study conducted by Rothova M, Thompson H, Lickert H, Tucker AS.(2012) exploring the historically debated issue of endoderm contribution to tongue development showed promising evidence that position of taste buds are patterned by the border of ectoderm and endoderm derivative epithelium. This study was accomplished via microscopic examination of previously stained specimens. Concluding endoderm has direct influence on gustatory development <ref><pubmed>22581563</pubmed></ref>

'''Changes in Taste Cells over time'''

Research by
Ozdener H, Spielman AI, Rawson NE.(2012) developing a culture which allows taste cells to survive for up to 12 months, empowers researchers to study the processes of proliferation, differentiation and function. This experiment will provide a precedent for future study of taste cells, as these cells are able to operate and grow normally. <ref><pubmed>22643728</pubmed></ref>

'''Shh key component of taste bud proginators'''

A [[#Glossary |'''tamoxifen''']] treatment which suppresses Sonic hedgehog (Shh) secretion in mice proving to reduce the number of cells visible within papillae, in contrast mice not treated with tamoxifen showed a mark increase of cells within papillae, these cells are assumed to become taste cells in later development.
Specific mice were bred to trace the destination of taste placode cells, the study concluded that Shh expressing placodes are taste bud proginators which in turn become taste cells within taste buds although do not have any precursors relationship with papillae. The results were obtain by examination of mice embryos using Bright-field or multichannel fluorescent images through the use of an "Axiocam CCD camera and Axioplan fluorescence microscope with Axiovision software" a study by Harlow, Yang, Williams, Barlow (2011)<ref><pubmed>PMC2674259</pubmed></ref>

'''WNT family exhibit various roles'''

[[File:Abnormal of tongue.jpg|thumb|200px|Image shows an example of tongue abnormalities, this is called "double tongue" each side has independent movement!]]

The WNT gene family has a function of signaling work antagonistically through receptor tyrosine kinase (RTK) signaling. However, the deletion of Sprouty Homolog 2 (Spry2) led to the increase of chimaeric virus particles (CVPs) and a significant decrease in number of fungiform papillae. In contrast, the absence of Fibroblast growth factor 10 (Fgf10) in conjunction with absence of CVPs lead to an increase in number and size of fungiform papillae. Therefore these genes have different effects on the anterior and posterior developing tongue and taste buds. In 2010 Liu, Staubach Grosse, Walton, Saims, Gumucio, Mistretta explored recent findings on the role of WNT's in tongue and papillae development, Concluding that WNT/β-catenin is essential for fungiform papillae differing to WNT5a which proved to be principle in tongue development. Intrinsic chemical mediators were considered by manipulating a tissue culture and then thoroughly examined by scanning photomicrograph. <ref><pubmed>PMC2768563</pubmed></ref>

[[File:Developing_tongue_histology_001.jpg|right|thumb|200px|HIstological stain of a developing rat tongue]]

==Glossary==

* '''Circumvallate papillae''' -

* '''Ectoderm'''- outer germ layer of embryo

* '''Endoderm''' - inner germ layer of embryo

* '''Epithelium''' - basic animal tissue that is composed of tightly packed cells, usually covering the outer portion of organs

* '''Exocystosis''' - movement of contents out of cell

* '''Filiform papillae''' -

* '''Foliate papillae''' -

* '''Fungiform papillae''' -

* '''Ganglia''' - the accumulation of a nerve cell body

* '''Growth factor''' - a substance that stimulates the growth of cells

* '''Gustatory''' - anything that relates to the taste sense

* '''Hydrolysis''' - breakdown of a chemical when it reacts with water

* '''Mesoderm''' - middle germ layer of embryo

* '''Mesenchyme''' - multipotential cells

* '''Neural crest''' - a part of the ectoderm found on both sides of the neural tube

* '''Neuron''' - most simplistic unit of the nervous system

* '''Neurotransmitter''' - chemicals which allow the passing of signals from neuron to neuron via connecting part (synapse)

* '''Papillae''' - small rough surface projection

* '''Six genes''' - a family of genes

* '''Sonic hedgehog (Shh)''' - signalling protein involved in normal development

* '''Sulcus terminalis''' - describes a physical transition point separating the anterior 2/3 of the tongue from the posterior 1/3

* '''Tamoxifen''' - hormonal altering drug

* '''Type I taste cells''' - The most abundant cells in taste buds; involved in terminating synaptic transmissions (similar to the role of glial cells in the CNS).

* '''Type II taste cells''' - Receptor cells acting as primary detectors of sweet, bitter or umami taste.

* '''Type III taste cells''' - Presynaptic cells that respond to sweet, salty, sour, bitter and umami compounds.

== References ==
<references/>

==External Links==
{{External Links}}

1.[http://www.surgicalneurologyint.com/article.asp?issn=2152-7806;year=2012;volume=3;issue=1;spage=23;epage=23;aulast=Manjila]

2.[http://embryology.med.unsw.edu.au/embryology/index.php?title=2012_Group_Project_4]

3.[http://www.webmd.com/oral-health/picture-of-the-tongue]

4.[http://www.tutorvista.com/content/biology/biology-iv/nervous-coordination/tongue-structure.php#parts-of-tongue]

5.[http://www.cf.ac.uk/biosi/staffinfo/jacob/teaching/sensory/taste.html]

--[[User:Z8600021|Mark Hill]] 12:22, 15 August 2012 (EST) Please leave the content listed below the line at the bottom of your project page.

----

{{2012Projects}}

2012 Group Project 3

2012-10-03T00:58:31Z

Z3330986: /* Neuronal Development */

=Taste Development=

You are out to dinner and your meal arrives in front of you, the aromas and the presentation of your food strikes you immediately. Half way through, the waiter returns and asks “How does your meal taste?” The answer is not as simple as one might think. Why does the meal taste pleasant? How do we experience different tastes? In the following page, we aim to discern how exactly one would answer these questions by looking at the embryological development of the taste system from week to week.

Taste is a complex sensory system and its precise workings are to this day not fully understood. What makes it so complicated is the interaction between the structure of tongue and taste buds and how this contributes to the representation of taste qualities (salty, bitter, sweet, sour and umami) in the brain. We will also look at some current research on animal models being undertaken to evaluate the role of specific genes in the development of sensory structures. By looking at the taste system’s genetic basis, we now have a greater understanding of the abnormalities that may occur during development and a direction to pursue in future research to attempt to fill in the gaps of scientific knowledge.

==Adult Tongue and Taste Buds – Structure and Function==

'''Structure'''

The tongue is located on the floor of the oral cavity, It is a muscular structure with sensory units crowning. The tongue is divided into an anterior two thirds and a posterior one third. These regions are divided by a V-shaped groove at the back of the tongue (sulcus terminalis). The anterior two thirds of the tongue is covered by stratified squamous epithelium, It contains a roughened surface and has projections called papillae that vary in shape and number.

[http://www.webmd.com/oral-health/picture-of-the-tongue]

''''The image below is a simplistic diagram of the surface of the tongue showing the locations of the different papillae and other important features'''

{|
| [[Image:Drawing of Tongue.png|centre|500px]]

[[File:Taste_pathway.jpg|right|thumb|200px|Simplistic Pathway of Taste]]

'''Papillae'''

There are 4 types of papillae on the tongue.
The most numerous papillae are the filiform papillae, which function to provide a surface that aids in holding food on the tongue during chewing but do not contain taste buds. The larger, less numerous fungiform papillae which contain taste buds, as do foliate papillae. Circumvallate papillae form a wide V at the sulcus terminalis also containing taste bus. There are no papillae or taste buds located on the posterior third of the tongue, having mucosal folds and the lingual tonsils instead.[http://www.tutorvista.com/content/biology/biology-iv/nervous-coordination/tongue-structure.php#parts-of-tongue]

[[File:Papillae.jpg|Left|thumb|200px|Close up of Human Tongue Papillae]]

[[File:Fungiformpapillae.jpg|left|thumb|200px|Fungiform Papillae]]

[[File:Circumvallatepapillae.jpg |left|thumb|200px|Circumvallate Papillae]]

[[File:Filiformpapillae.jpg|left|200px|thumb|Foliate Papillae]]

'''Function'''

The Tongue has muscular and sensory functions, muscular functions include swallowing and speech where as sensory function involves taste. This section will focus on the sensory functions of the tongue.
The functional unit of the taste bud is a taste cell, there are between 50 and 100 taste cells in each taste bud these taste cells represent all 5 different tastes. Historically is was believed that different areas of the tongue were responsible for different taste sensations although this has since been disregarded.[http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/W/Welcome.html] The papillae contain taste buds which are connected to the oral cavity via a taste pore, the function of the taste bud is to transmit a chemical signal from the oral cavity to a taste cell, this chemical signal is the converted into an electrical impulse and delivered to the brain via nerve fibres for interpretation. [http://www.cf.ac.uk/biosi/staffinfo/jacob/teaching/sensory/taste.html]

[[File:Taste_bud_1.jpg|right|thumb|200px|Cross section of a taste bud unit|centre|Cross section of a taste bud unit]]

'''Link Between Taste and Smell'''

The pathways of smell and taste are very similar (chemosensation). Pathways both involve the conversion of a dissolved chemical stimulus transformed into a electrical impulse for interpretation by the brain.
Taste and smell overlap when humans experience flavour, flavour involves an interaction of taste, smell, texture and temperature, where taste is only a portion of this interaction. when the brain interprets a flavour, contribution from other senses has a significant role in identification. In conclusion Taste and Smell in combination with other senses help develop a sensory interpretation called flavour.[http://www.entnet.org/HealthInformation/smellTaste.cfm]
[[File:Human smelling.jpg|500px|centre]]

==History of Discoveries==

{| cellpadding=5 style="border:1px solid #BBB"
|- bgcolor="#faecc8"
|''' Date'''|| '''Significant Discovery'''

|- bgcolor="#faf6ed"
|'''350BC'''
|| Aristotle writes about the basic tastes, sweet and bitter. He also notes that it can be modified by salty and acidic. <ref name="PMID22717400"><pubmed>22717400</pubmed></ref>

|- bgcolor="#faecc8"
|'''1901'''
|| D. Hanig publishes a paper describing taste sensitivity in different regions of the tongue.
''Interesting fact:'' The modern concept of a 'tongue map' is a misinterpretation of this study. <ref name="PMID22717400"/>

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''1908'''
|Kikunae Ikeda, a professor of the Tokyo Imperial University, discovered and identified the fifth basic taste: umami (savouriness), made palatable by glutamate. <ref><pubmed>12438213</pubmed></ref>
[http://chemse.oxfordjournals.org/content/27/9/847.long New Seasonings]

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''1931-32'''
| A chemist named Arthur Fox and his college noted that they had different sensitivities to the bitter tasting Phenylthiocarbamide (PTC).<ref>Blakeslee AF, Fox AL. Our different taste worlds. J Hered. 1932;23:97–107.</ref> Geneticists later confirm these findings, and discover that non-tasting is a recessive genetic trait. <ref><pubmed>17782493</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pubmed/17782493 Inherited taste deficiency]

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''1965'''
|Farbman's study of the developing taste but in rat fungiform papilla was significant in increasing our understanding of taste bud development. <ref><pubmed>14300090</pubmed></ref>
[http://www.sciencedirect.com/science/article/pii/0012160665900400 Electron microscope study of the developing taste bud in rat fungiform papilla.]

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''1992'''
|McLaughlin SK et al. discovery a taste cell-specific G-protein within the taste buds called Gustucon. This protein is later used to mark bitter, umami and sweet cells. <ref><pubmed>1608467 </pubmed></ref>
[http://www.nature.com/nature/journal/v357/n6379/abs/357563a0.html Gustducin is a taste-cell-specific G protein closely related to the transducins]

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''1995'''
|Barlow et al. experimented with Axolotl salamanders and concluded that taste buds from this species arise exclusively from epithelial tissue, "oropharyngeal [[#Glossary |'''epithelium''']]". <ref name="PMID17826760"><pubmed>17826760</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pubmed/17826760 Embryonic origin of gustatory cranial sensory neurons]

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''1996'''
| Witt M and Reutter K of the Technical University Dresden in Germany, carried out a transmission electron microscopy study to investigate the embryonic and fetal development of Human taste buds. Their results suggest an "at least dual function of embryonic/fetal taste buds", including non-gustatory, paracrine functions prior to the 14th week and gustatory after the 14th week. <ref name="PMID8955790"><pubmed>8955790</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pubmed/8955790 Embryonic and early fetal development of human taste buds: a transmission electron microscopical study]

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''2000'''
|Chandrashekar, J. et al. discover the first taste sonsors, the T2R bitter taste receptors. <ref><pubmed>10761935</pubmed></ref>
[http://www.sciencedirect.com/science/article/pii/S0092867400807060 T2Rs Function as Bitter Taste Receptors]

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''2001'''
|Nelson, G. et al. discover the sweet receptor: a combination of T1R2 and T1R3. <ref><pubmed>11509186</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pubmed/11509186?dopt=Abstract&holding=npg Mammalian sweet taste receptors.]

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''2002'''
|Nelson G. et al. discover the amino acid (umami) taste receptor: a combination of T1R1 and T1R3 identified. <ref><pubmed>11894099</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pubmed/11894099?dopt=Abstract&holding=npg An amino-acid taste receptor]

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''2005'''
|Dyer, J. et al. discover sweet taste receptors in the GI tract. <ref><pubmed>17855558</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1986582/ Sweet taste signaling in the gut]

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''2006'''
|Huang, A. L et al. discover cells for sour taste, identified by PKD2L1 (a polycystic kidney disease-like ion channel). <ref><pubmed>16929298</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1571047/ The Cells and Logic for Mammalian Sour Taste detection]

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''2007'''
|Harlow DE, Barlow LA of the University of Colorado Denver Health Sciences Center provide evidence of the "embryonic origin of gustatory cranial sensory neurons". <ref name="PMID17826760"/>
[http://www.ncbi.nlm.nih.gov/pubmed/17826760 Embryonic origin of gustatory cranial sensory neurons.]

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''2009'''
|A study by Hevezi P et al, presents "the first comprehensive characterization of gene expression in primate taste buds", as opposed to previous studies which focused on rodents. <ref><pubmed>19636377</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pubmed/19636377 Genome-wide analysis of gene expression in primate taste buds reveals links to diverse processes]

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''2010'''
|Chandrashekar, J. et al. identify epithelial sodium channel (ENaC) as the sodium-salt taste receptor. <ref><pubmed>20107438</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pubmed/20107438?dopt=Abstract&holding=npg The cells and peripheral representation of sodium taste in mice]
|}

== Human Weekly Development - Two Prominent Studies ==
Martin Witt and Klaus Reutter of the University of Tubingen in Germany published two prominent studies regarding developing taste buds in humans. Their first study in 1996 was a transmission electron microscopical (TEM) study of the taste bud primordium and its morphological changes during the 8th-15th postovulatory week. Their next study in 1997 built on their previous findings by using Scanning Electron Microscopy (SEM) to observe the development of gustatory [[#Glossary |'''papillae''']] during postovulatory weeks 6-15.

The findings of these two studies are summarized in the table below. The figures provided relate to the images on their respective research papers.

# [http://onlinelibrary.wiley.com/doi/10.1002/(SICI)1097-0185(199612)246:4%3C507::AID-AR10%3E3.0.CO;2-S/pdf Embryonic and early fetal development of human taste buds: a transmission electron microscopical study, 1996]
# [http://chemse.oxfordjournals.org/content/22/6/601.long Scanning electron microscopical studies of developing gustatory papillae in humans, 1997]

===Timeline of Developmental Processes of Human Taste Buds===
{| cellpadding=5 style="border:1px solid #BBB"
|- bgcolor="#89CFF0"
|'''Postovulatory Week'''||'''Description'''

|- bgcolor="#BCD4E6"
|'''Week 6''' ||
The surface of the developing tongue is covered by nearly flat epithelium (1997, Figure 1). The first gustatory papillae of the tongue appear in the caudal mid-line near the foramen caecum and the first circumvallate papilla develops on the dorsal mid-line. <ref name="PMID9455607"><pubmed>9455607</pubmed></ref>

|- bgcolor="#89CFF0"
| '''Weeks 6 to 7'''||
Nerve fibers approach the basal lamina of lingual epithelium. At this stage the lingual epithelium consists of two to three cell layers and there is not yet any sign of cell specializations indicating early taste bud formation. <ref name=PMID8955790/>

|- bgcolor="#BCD4E6"
| '''Week 7 '''||
A series of irregular epithelial swellings in the anterior part and marginal parts of the tongue indicate early forming fungiform papillae. Furthermore, a V-like lane is observed anterior to the [[#Glossary |'''sulcus terminalis''']], which represents a smooth surface for developing circumvallate papillae (1997, Figure 2). Witt M et al observe that these circumvallate papillae are larger than the developing fungiform papillae of the same age, later noting that the fungiform papillae tend to increase in size over the 8-15th weeks of gestation, whilst the size of vallate papillae tend to remain constant during this period. <ref name=PMID9455607/>

|- bgcolor="#89CFF0"
| ''' Week 8 ''' ||
* The taste bud primordium are still differentiated, elongated epithelial cells, resting on a slightly developed core of young dermal papilla.
* The lingual epithelium shows first signs of taste bud development as nerve fibers coming from the dermal papilla penetrate the epithelial basal lamina and form synapses with taste bud progenitor cells (1996, Figure 1). These synapses demonstrate the neuronal connection between the taste bud primordium and the central nervous system, reaching a maximum around the 12th to 13th week. However, it is important to note that at this time these cells are still poorly differentiated, elongated epithelial cells.
* Ciliated cells also appear around the 8th week, however the significance of these cells which are scattered randomly across the lingual surface remains unclear. <ref name=PMID8955790/>

|- bgcolor="#BCD4E6"
|''' Week 9''' ||
By this stage, although a taste pore is not present, the surface of circumvallate papillae usually contains a taste pit partly filled with microvillus-like processes from the underlying taste bud cells (1997, Figure 10). <ref name=PMID9455607/>

|- bgcolor="#89CFF0"
|''' Weeks 10-11''' ||
At this stage, the lingual epithelium compromises of about four cell layers, and the first shallow grooves above the taste bud primordium are developed. Fungiform papillae appear on the lateral margins and the tip of the tongue, containing taste bud primordial that display the first signs of a primitive pore formation (1996, Figure 6). <ref name=PMID8955790/>

|- bgcolor="#BCD4E6"
|''' Week 12 ''' ||
Taste bud cells are more clearly differentiated into epithelial cell types II and III. <ref name=PMID8955790/>

|- bgcolor="#89CFF0"
|''' Weeks 12-13 ''' ||
At this stage the taste bud primordial are all located on the top of dermal papillae. There is also maximum synapses between cells and afferent nerve fibers, which intermingle with each other to form a plexus-like structure (1996, Figure 6a). <ref name=PMID8955790/>

|- bgcolor="#BCD4E6"
|''' Weeks 14 -15 ''' ||
The shape and size of the taste buds primordial begins to resemble those of adult taste buds (1996, Figure 9). By the 14th week the taste pores develop as the taste pits are filled by microvilli, and bubble like vesicles indicate the secretory activity of these cells (1996, Figure 10). However, the taste buds only achieve a fully developed function in week 15 of gestation with the development of type I cells to produce the mucous material in the taste pit. <ref name=PMID8955790/>
|}

==Abnormalities==

It should be mentioned that gustatory abnormalities have not been widely researched. Most research conducted in this field has been conducted through animal testing on mice and this is the basis of information provided below.

===Knocking out P2X Receptors===

[[File:Image of taste being evoked by visualising ATP release.jpeg|Left|thumb|200px|Evoking taste - ATP release in tongue]]

In Huang, 2008 this team used the release of the [[#Glossary |'''ectoderm''']], ATP (adenosine triphosphate) as a quantitative measurement of gustatory sensation and taste. This was done by using a comparison of wild type (WT) and double knockout (DKO) mice. P2X receptors, P2X2 and P2X3 were knocked out in the DKO mice. The premise of this article was that knocking out P2X receptors reduces transmitter secretion of ATP in taste buds, therefore they cannot taste.

It should be noted that the taste buds in DKO are functional, but are not stimulated by the administration of tastants.

The transmission of release of ATP is secretion through gap junction hemichannels (pannexin 1 gap junction).

When both P2X2 and P2X3 are knocked out, no taste is elicited. However they found that if either P2X2 OR P2X3 was knocked out there was a taste response. So the inference made from this is that if one of the two receptors from the P2X family was knocked out there still can have taste response. The WT mice showed significant stimulation by tastants whereas DKO had little to no stimulation of ATP release.<ref><pubmed>21940456</pubmed></ref>

===FGF signalling and genes===

Sprouty, or ''Srpy'', genes have been related to regulating the development of circumvallate papillae (CVP). The CVP are large dome shaped papillae, which form a 'V' just in front of the terminal sulcus.

By knocking out ''Spry'' genes using mice which had ''Spry1'' and ''Spry2'' knocked out showed that the number of CVP doubled. However, when Fibroblast [[#Glossary |'''Growth Factor''']] gene ("Fgf10") was absent, the number of CVP was significantly reduced, if not completely absent. The correlation between ''Spry1/2'' and ''Fgf10'' is that ''Spry1/2'' antagonizes "Fgf10" to limit the size of the CVP progenitor placode. Exclusive expression of ''Fgf10'' in the [[#Glossary |'''mesenchyme''']] is necessary for the formation of CVP.

'''This image shows the CVP stained with H&E and scanned by Scanning Electron Microscope (SEM)'''
[[File:CVP of WT(top) and DKO(bottom) mice with H&E and SEM.png]]

'''This image shows the location of the CVP and the increased number in DKO mice by SEM'''
[[File:Mouse circumvallate papilla 01.jpg|300px]]

Taste buds develop from the mesenchyme but require local signalling to properly differentiate. Some signalling factors for proper development of taste buds besides FGF are: [[#Glossary |'''Sonic Hedgehog''']] (SHH), Bone Morphogenetic Proteins (BMPs), Epidermal Growth Factor (EGF).

Additionally, this proves that the anterior and posterior developments of the tongue are derived from embryonic tissues, where the anterior tongue is derived from the [[#Glossary |'''ectoderm''']] and the posterior tongue is derived from the [[#Glossary |'''endoderm''']]. Taste buds develop from the mesenchyme but require local signalling to properly differentiate. Some signalling factors for proper development of taste buds besides FGF are: Sonic Hedgehog (SHH), Bone Morphogenetic Proteins (BMPs), Epidermal Growth Factor (EGF).

As mentioned above, this article shows that the anterior and posterior developments of the tongue are derived from embryonic tissues, where the anterior tongue is derived front the ectoderm and the posterior tongue is derived from the endoderm. Secondly, FGF is required to regulate the growth of taste buds, while ''Spry'' genes limit the number of CVP. ''Fgf10''& ''Spry 1&2''work antagonistically through receptor tyrosine kinase (RTK)signalling.

However, the deletion of ''Spry2''led to the increase of CVPs it should be noted that they found that a significant decrease in number of fungiform papillae. In contrast, the absence of ''Fgf10'', while leading to the absence of CVPs lead to an increase in number and size of fungiform papillae. Therefore these genes have different effects on the anterior and posterior developing tongue and taste buds.<ref><pubmed>21655085</pubmed></ref>

==Gustatory System==

[[Image:Taste qualities.gif|thumb|The five basic tastes]]

Taste or more appropriately gustation, is a fundamental survival tool in animals as it directs the consumption of essential nutrients. The five tastes that exist within the human gustatory system: salty, sweet, sour, bitter and umami, all signify basic physiological requirements. Salty tastes denote the presence of Na+, an important ion involved in the transportation and retention of water across cell membranes. Sweetness is the recognition of carbohydrates, essential for maintaining optimal brain function and providing the basis for energy production in muscle tissue via ATP [[#Glossary |'''hydrolysis''']]. Similarly umami codes for the presence of L-amino acids, especially L-glutamate which is an integral component of protein synthesis.

These different modalities not only function to maintain the proper intake of nutrients within the body but also, by way of aversion, prohibit the consumption of undesired or poisonous materials. The bitter modality for example is generally regarded as displeasing to the human palate. It represents a high acid content which may be a result of foods which have become rotten or are inherently poisonous to the body.<ref name=PMID20696704><pubmed>20696704</pubmed></ref>

Research has historically limited itself to investigating the mechanisms of these five taste qualities though it must be noted many other modalities may exist. Of particular conjecture is the existence of fatty acid recognition. In the past the detection of fat in food has been attributed to somatosensory inputs <ref name=PMID20696704/> from the tongue, that is, the oily feel and texture of fat rather than its actual ‘taste’ allows the brain to encode for its presence. Further research is therefore required to elicit the precise mechanisms of fat detection.

===Cell Biology===

The five taste qualities are not all detected by the same type of receptor cell located within the taste bud. Like rods and cones in the eye which detect different wavelengths of light, there are specific types of receptors for different tastes. For example, sweet, umami and bitter are recognized by Type II G-protein coupled receptors, whereas sour is related to Type III presynaptic cells. The cell type involved in salty taste transduction is unknown however it is known that sodium ions can enter the receptor cell membrane via ion channel permeation.

====Type II receptors====

When a bitter, sweet or umami ligand binds to a type II G-coupled receptor, a cascade of chemical reactions causes the release of Ca2+ which in turn mediates [[#Glossary |'''exocystosis''']] of ATP. The function of this ATP is threefold:

# Stimulates gustatory nerve afferents which project to gustatory nuclei in the spinal cord
# Excites Type III presynaptic nerve fibers to release serotonin.
# Has a positive feedback effect on type II receptor cells, increasing the level of ATP production.

The role of serotonin is believed to be in the form of lateral inhibition i.e. when a bitter quality is recognized, adjacent receptors for sweetness are deactivated and thus the two tastes may be clearly differentiated. It also has a negative feedback effect on receptor cells, inhibiting umami, bitter and sweet taste transduction.

==Taste Map==
[[Image:Taste map.png|thumb|left|250px|Obsolete idea of the tongue map]]
The idea of a tongue map has disseminated through society for many years. This concept purports that different areas of the tongue are specialized to detect either sweet, salty, sour and bitter tastes. Recent research however has completely nullified such claims and suggests instead that different forms of taste are recognized all over the tongue as well as via the palate. Thus the term ''taste map'' has come to take on a new meaning and that is, the precise areas of taste modalities processing in areas of cortex and its subsequent neural inputs.

===Neural Pathways===

'''First order [[#Glossary |'''neuron''']]''' - From the receptors located in the taste buds, gustatory nerve afferents project to the ipsilateral rostral 1/3 of the nucleus tractus solitarius (NTS), located in the medulla. This rostral 1/3 is commonly referred to as the ''gustatory nucleus''.

The ''gustatory nucleus'' receives input from cranial nerves VII (''Facial n.''), IX (''Hypglossal n.''), and X (''Vagus n.'') via special visceral afferent (SVA) nerve fibers. A summary of their functions is as follows:

* ''Facial nerve n''. - carries taste information from the anterior 2/3 of the tongue.
* ''Hypoglossal n.'' - carries taste information from the posterior 1/3 of the tongue.
* ''Vagus n''. - carries taste information from the palate

'''Second order neurons''' - From the NTS second order neurons carry taste information to the Ventral posteromedial (VPM) nucleus in the thalamus.<ref name=PMID21885776/>

Copious scientific conjecture surrounds how each taste modality is transmitted to the brain. The ‘labelled-line’ hypothesis suggests that there are taste specific neurons which exclusively carry that taste modality to cortical areas. In analogous terms it can be viewed like the pipelines leading toward a house. Each pipeline carries its own utility, there is one for gas, another for water and finally for electricity with each terminating in slightly different areas of the house. In the same way, on the tongues there are different receptors for each taste which concurrently have individual nerve tracts leading to the primary gustatory cortex.

Contrapuntally there is electrophysiological evidence that single nerve afferents carry multiple modalities. These studies show one nerve afferent may have both a strong and a weak activation in response to a multiple taste stimuli.

===Cortical Areas===

[[Image:Primary gustatory cortex.png|thumb|Primary gustatory cortex]]

The location of the taste perception centers has been observed via functional magnetic resonance imaging (fMRI) studies. The primary taste cortex has been identified as being located in the anterior insula/frontal operculum (I/fO)<ref name=PMID22245354><pubmed>22245354</pubmed></ref>, with the secondary taste cortex in the caudolateral orbitofrontal cortex.<ref name=PMID21305668><pubmed>21305668</pubmed></ref> Within the insula there are further subdivisions related to each taste modality. Two photon calcium imaging research has outlined certain ’hot-spots’ of activation which are clearly delineated in relation to each taste. For example, the bitter modality is represented on the insula cortex approximately 1mm posterior to the middle cerebral artery whereas the sweet modality is represented 2.5mm rostrodorsal to the bitter field with no apparent overlap.<ref name=PMID21885776><pubmed>21885776</pubmed></ref> These findings lend weight to the idea that there is only one receptor for each taste quality.

It is interesting to note the relationship between taste and the reward centers of the brain. There is evidence of neural input to the ventral tegmental area (the origin of the mesolimbic dopaminergic reward pathway) and nucleus accumbens (involved in the conversion of motivation into physical action).<ref name=PMID21885776/> Neural connections such as this provide the foundations in explaining concepts such as flavour learning and preference. It may also give some insight into chronic problems such as food addiction and craving. As of yet however the gustatory neural network is not well understood and more research is required to elucidate the relationship between pleasure and taste sensation

===Neuronal Development===

The gustatory system must not be solely thought of as being comprised of simply the tongue and palate. The types of neurons which carry taste information to the brain are also pivotal in constructing the expression of taste qualities.

The two main gustatory neurons which develop are the geniculate ganglion and the petrosal ganglion. These are the visceral sensory ganglion of cranial nerves VII (Facial) and IX (Hypoglossal) respectively which carry taste information from the tongue to the nucleus tractus solitarius.<ref name=PMC2078608><pubmed>2078608</pubmed></ref> They arise at the posterior placodal region from the epibranchial placodes, a thickening of ectoderm. The first epibranchial placode gives rise to the geniculate ganglion and the second to the petrosal ganglion.<ref name=PMC1995452><pubmed>1995452</pubmed></ref>

The molecular basis for gustatory neuron formation is not completely understood though there are a number of transcription factors which are thought to play an important role in firstly, placode formation and secondly, neuron differentiation.

*Six1/2, Six1/5 and Eya – transcription factors which cause differentiation of epibranchial placodes into the petrosal and geniculate ganglion.
*Bone morphogenic Protein 7 (BMP7) – a signal arising from the pharyngeal pouch which is believed to induce epibranchial placode formation. May not be solely responsible for this process, current research has been inconclusive as to how it may work with other proteins of the same family.
*NGN2 - Following the initial differentiation of the placodes, further differentiation occurs to form neuroblasts. NGN2 causes the delamination and migration of these neuroblasts, which subsequently migrate and fuse to form neurons.<ref name=PMC1995452><pubmed>1995452</pubmed></ref>
*Phox2b – maintains the structural integrity of neurons. Knockout of these genes in mice causes marked atrophy of the petrosal and geniculate ganglia.

The neurons involved in the gustatory system are overproduced and thus in the embryonic stage, undergo programmed cell death (apoptosis). The total amount of neurons in the geniculate ganglion, appears to be quite stable over the embryonic stages. This suggests, unlike the petrosal ganglion, the levels of neuroblast proliferation and apoptosis are fairly similar. The factors which regulate these processes remains unclear. It is posited that neurotrophins BDNF, NT4/5 and NT3 may regulate neuronal survival<ref name=PMC3070660><pubmed>3070660</pubmed></ref> whilst also playing a part in axon growth from the sensory ganglion. More research is required to discern the exact individual functions of each of the neurotrophins.

==Current Research==

[[File:Mousetounge histologicalstain.jpg|right|thumb|200px|Image shows histological stains of a mice tongue showing dysplasia]]

We have an evolving understanding of Embryonic Taste development, through the use of state-of-the-art technology and research techniques we are able to make brilliant discoveries that continue to connect the dots of this amazing natural process of human development.
The majority of research in taste development is involving mice, these mammals show similar embryonic pathways to humans and research is performed in ethical and humane methods.

'''Synergistic relationships of Six Genes '''

In an animal study using mice by Suzuki Y, Ikeda K, Kawakami K.(2011) Firstly nominating "[[#Glossary |'''Six Genes''']]" as a major component in [[#Glossary |'''gustatory ''']] development, stating that deficiencies in certain Six genes (specifically Six1 & Six4) leads to poor development. Their research also highlights evidence of cooperative relationships between Six genes for normal advance. This experiment involved breeding mice containing exclusively Six1 and Six4 genes and examining the expression of these genes in papillae under high powered microscope observation. Understanding the role of certain genes along with the intrinsic relationships they hold is crucial for the ability to identify possible causes and correction of any abnormalities <ref><pubmed>21978088</pubmed></ref>

[[File:Highpowered_microscope.jpg|Left|thumb|200px|Image of a high powered microscope]]

'''Neural Crest responsibilities '''

Another Animal Study involving mice explores a new idea of [[#Glossary |'''Neural crest''']] (NC) contribution in taste development, specifically the development of papillae and taste buds. Liu HX, Komatsu Y, Mishina Y, Mistretta CM. (2012) suggest that Neural crest cells travel to the location of the tongue in early embryonic stages, gain epithelium phenotypes, multiply and then differentiate to eventually form taste papillae. The experiment involved the comparison of 2 different types of Cre line mice, which both express Cre gene in neural crest protocol, the different distribution patterns where observed in specific regions that NC is responsible for.<ref><pubmed>22659543</pubmed></ref>

'''Augmentation of Endoderm'''

In an animal study conducted by Rothova M, Thompson H, Lickert H, Tucker AS.(2012) exploring the historically debated issue of endoderm contribution to tongue development showed promising evidence that position of taste buds are patterned by the border of ectoderm and endoderm derivative epithelium. This study was accomplished via microscopic examination of previously stained specimens. Concluding endoderm has direct influence on gustatory development <ref><pubmed>22581563</pubmed></ref>

'''Changes in Taste Cells over time'''

Research by
Ozdener H, Spielman AI, Rawson NE.(2012) developing a culture which allows taste cells to survive for up to 12 months, empowers researchers to study the processes of proliferation, differentiation and function. This experiment will provide a precedent for future study of taste cells, as these cells are able to operate and grow normally. <ref><pubmed>22643728</pubmed></ref>

'''Shh key component of taste bud proginators'''

A [[#Glossary |'''tamoxifen''']] treatment which suppresses Sonic hedgehog (Shh) secretion in mice proving to reduce the number of cells visible within papillae, in contrast mice not treated with tamoxifen showed a mark increase of cells within papillae, these cells are assumed to become taste cells in later development.
Specific mice were bred to trace the destination of taste placode cells, the study concluded that Shh expressing placodes are taste bud proginators which in turn become taste cells within taste buds although do not have any precursors relationship with papillae. The results were obtain by examination of mice embryos using Bright-field or multichannel fluorescent images through the use of an "Axiocam CCD camera and Axioplan fluorescence microscope with Axiovision software" a study by Harlow, Yang, Williams, Barlow (2011)<ref><pubmed>PMC2674259</pubmed></ref>

'''WNT family exhibit various roles'''

[[File:Abnormal of tongue.jpg|thumb|200px|Image shows an example of tongue abnormalities, this is called "double tongue" each side has independent movement!]]

The WNT gene family has a function of signaling work antagonistically through receptor tyrosine kinase (RTK) signaling. However, the deletion of Sprouty Homolog 2 (Spry2) led to the increase of chimaeric virus particles (CVPs) and a significant decrease in number of fungiform papillae. In contrast, the absence of Fibroblast growth factor 10 (Fgf10) in conjunction with absence of CVPs lead to an increase in number and size of fungiform papillae. Therefore these genes have different effects on the anterior and posterior developing tongue and taste buds. In 2010 Liu, Staubach Grosse, Walton, Saims, Gumucio, Mistretta explored recent findings on the role of WNT's in tongue and papillae development, Concluding that WNT/β-catenin is essential for fungiform papillae differing to WNT5a which proved to be principle in tongue development. Intrinsic chemical mediators were considered by manipulating a tissue culture and then thoroughly examined by scanning photomicrograph. <ref><pubmed>PMC2768563</pubmed></ref>

[[File:Developing_tongue_histology_001.jpg|right|thumb|200px|HIstological stain of a developing rat tongue]]

==Glossary==

* '''Circumvallate papillae''' -

* '''Ectoderm'''- outer germ layer of embryo

* '''Endoderm''' - inner germ layer of embryo

* '''Epithelium''' - basic animal tissue that is composed of tightly packed cells, usually covering the outer portion of organs

* '''Exocystosis''' - movement of contents out of cell

* '''Filiform papillae''' -

* '''Foliate papillae''' -

* '''Fungiform papillae''' -

* '''Ganglia''' - the accumulation of a nerve cell body

* '''Growth factor''' - a substance that stimulates the growth of cells

* '''Gustatory''' - anything that relates to the taste sense

* '''Hydrolysis''' - breakdown of a chemical when it reacts with water

* '''Mesoderm''' - middle germ layer of embryo

* '''Mesenchyme''' - multipotential cells

* '''Neural crest''' - a part of the ectoderm found on both sides of the neural tube

* '''Neuron''' - most simplistic unit of the nervous system

* '''Neurotransmitter''' - chemicals which allow the passing of signals from neuron to neuron via connecting part (synapse)

* '''Papillae''' - small rough surface projection

* '''Six genes''' - a family of genes

* '''Sonic hedgehog (Shh)''' - signalling protein involved in normal development

* '''Sulcus terminalis''' - describes a physical transition point separating the anterior 2/3 of the tongue from the posterior 1/3

* '''Tamoxifen''' - hormonal altering drug

* '''Type I taste cells''' - The most abundant cells in taste buds; involved in terminating synaptic transmissions (similar to the role of glial cells in the CNS).

* '''Type II taste cells''' - Receptor cells acting as primary detectors of sweet, bitter or umami taste.

* '''Type III taste cells''' - Presynaptic cells that respond to sweet, salty, sour, bitter and umami compounds.

== References ==
<references/>

==External Links==
{{External Links}}

1.[http://www.surgicalneurologyint.com/article.asp?issn=2152-7806;year=2012;volume=3;issue=1;spage=23;epage=23;aulast=Manjila]

2.[http://embryology.med.unsw.edu.au/embryology/index.php?title=2012_Group_Project_4]

3.[http://www.webmd.com/oral-health/picture-of-the-tongue]

4.[http://www.tutorvista.com/content/biology/biology-iv/nervous-coordination/tongue-structure.php#parts-of-tongue]

5.[http://www.cf.ac.uk/biosi/staffinfo/jacob/teaching/sensory/taste.html]

--[[User:Z8600021|Mark Hill]] 12:22, 15 August 2012 (EST) Please leave the content listed below the line at the bottom of your project page.

----

{{2012Projects}}

2012 Group Project 3

2012-10-03T00:29:49Z

Z3330986: /* Cortical Areas */

=Taste Development=

You are out to dinner and your meal arrives in front of you, the aromas and the presentation of your food strikes you immediately. Half way through, the waiter returns and asks “How does your meal taste?” The answer is not as simple as one might think. Why does the meal taste pleasant? How do we experience different tastes? In the following page, we aim to discern how exactly one would answer these questions by looking at the embryological development of the taste system from week to week.

Taste is a complex sensory system and its precise workings are to this day not fully understood. What makes it so complicated is the interaction between the structure of tongue and taste buds and how this contributes to the representation of taste qualities (salty, bitter, sweet, sour and umami) in the brain. We will also look at some current research on animal models being undertaken to evaluate the role of specific genes in the development of sensory structures. By looking at the taste system’s genetic basis, we now have a greater understanding of the abnormalities that may occur during development and a direction to pursue in future research to attempt to fill in the gaps of scientific knowledge.

==Adult Tongue and Taste Buds – Structure and Function==

'''Structure'''

The tongue is located on the floor of the oral cavity, It is a muscular structure with sensory units crowning. The tongue is divided into an anterior two thirds and a posterior one third. These regions are divided by a V-shaped groove at the back of the tongue (sulcus terminalis). The anterior two thirds of the tongue is covered by stratified squamous epithelium, It contains a roughened surface and has projections called papillae that vary in shape and number.

''''The image below is a simplistic diagram of the surface of the tongue showing the locations of the different papillae and other important features'''

{|
| [[Image:Drawing of Tongue.png|centre|500px]]

[[File:Taste_pathway.jpg|right|thumb|200px|Simplistic Pathway of Taste]]

'''Papillae'''

There are 4 types of papillae on the tongue.
The most numerous papillae are the filiform papillae, which function to provide a surface that aids in holding food on the tongue during chewing but do not contain taste buds. The larger, less numerous fungiform papillae which contain taste buds, as do foliate papillae. Circumvallate papillae form a wide V at the sulcus terminalis also containing taste bus. There are no papillae or taste buds located on the posterior third of the tongue, having mucosal folds and the lingual tonsils instead.

[[File:Papillae.jpg|Left|thumb|200px|Close up of Human Tongue Papillae]]

[[File:Fungiformpapillae.jpg|left|thumb|200px|Fungiform Papillae]]

[[File:Circumvallatepapillae.jpg |left|thumb|200px|Circumvallate Papillae]]

[[File:Filiformpapillae.jpg|left|200px|thumb|Foliate Papillae]]

'''Function'''

The Tongue has muscular and sensory functions, muscular functions include swallowing and speech where as sensory function involves taste. This section will focus on the sensory functions of the tongue.
The functional unit of the taste bud is a taste cell, there are between 50 and 100 taste cells in each taste bud these taste cells represent all 5 different tastes. Historically is was believed that different areas of the tongue were responsible for different taste sensations although this has since been disregarded.[http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/W/Welcome.html] The papillae contain taste buds which are connected to the oral cavity via a taste pore, the function of the taste bud is to transmit a chemical signal from the oral cavity to a taste cell, this chemical signal is the converted into an electrical impulse and delivered to the brain via nerve fibres for interpretation.

[[File:Taste_bud_1.jpg|right|thumb|200px|Cross section of a taste bud unit|centre|Cross section of a taste bud unit]]

'''Link Between Taste and Smell'''

The pathways of smell and taste are very similar. Pathways both involve the conversion of a dissolved chemical stimulus transformed into a electrical impulse for interpretation by the brain.
Taste and smell overlap when humans experience flavour, flavour involves an interaction of taste, smell, texture and temperature, where taste is only a portion of this interaction. when the brain interprets a flavour, contribution from other senses has a significant role in identification. In conclusion Taste and Smell in combination with other senses help develop a sensory interpretation called flavour.
[[File:Human smelling.jpg|500px|centre]]

==History of Discoveries==

{| cellpadding=5 style="border:1px solid #BBB"
|- bgcolor="#faecc8"
|''' Date'''|| '''Significant Discovery'''

|- bgcolor="#faf6ed"
|'''350BC'''
|| Aristotle writes about the basic tastes, sweet and bitter. He also notes that it can be modified by salty and acidic. <ref name="PMID22717400"><pubmed>22717400</pubmed></ref>

|- bgcolor="#faecc8"
|'''1901'''
|| D. Hanig publishes a paper describing taste sensitivity in different regions of the tongue.
''Interesting fact:'' The modern concept of a 'tongue map' is a misinterpretation of this study. <ref name="PMID22717400"/>

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''1908'''
|Kikunae Ikeda, a professor of the Tokyo Imperial University, discovered and identified the fifth basic taste: umami (savouriness), made palatable by glutamate. <ref><pubmed>12438213</pubmed></ref>
[http://chemse.oxfordjournals.org/content/27/9/847.long New Seasonings]

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''1931-32'''
| A chemist named Arthur Fox and his college noted that they had different sensitivities to the bitter tasting Phenylthiocarbamide (PTC).<ref>Blakeslee AF, Fox AL. Our different taste worlds. J Hered. 1932;23:97–107.</ref> Geneticists later confirm these findings, and discover that non-tasting is a recessive genetic trait. <ref><pubmed>17782493</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pubmed/17782493 Inherited taste deficiency]

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''1965'''
|Farbman's study of the developing taste but in rat fungiform papilla was significant in increasing our understanding of taste bud development. <ref><pubmed>14300090</pubmed></ref>
[http://www.sciencedirect.com/science/article/pii/0012160665900400 Electron microscope study of the developing taste bud in rat fungiform papilla.]

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''1992'''
|McLaughlin SK et al. discovery a taste cell-specific G-protein within the taste buds called Gustucon. This protein is later used to mark bitter, umami and sweet cells. <ref><pubmed>1608467 </pubmed></ref>
[http://www.nature.com/nature/journal/v357/n6379/abs/357563a0.html Gustducin is a taste-cell-specific G protein closely related to the transducins]

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''1995'''
|Barlow et al. experimented with Axolotl salamanders and concluded that taste buds from this species arise exclusively from epithelial tissue, "oropharyngeal [[#Glossary |'''epithelium''']]". <ref name="PMID17826760"><pubmed>17826760</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pubmed/17826760 Embryonic origin of gustatory cranial sensory neurons]

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''1996'''
| Witt M and Reutter K of the Technical University Dresden in Germany, carried out a transmission electron microscopy study to investigate the embryonic and fetal development of Human taste buds. Their results suggest an "at least dual function of embryonic/fetal taste buds", including non-gustatory, paracrine functions prior to the 14th week and gustatory after the 14th week. <ref name="PMID8955790"><pubmed>8955790</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pubmed/8955790 Embryonic and early fetal development of human taste buds: a transmission electron microscopical study]

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''2000'''
|Chandrashekar, J. et al. discover the first taste sonsors, the T2R bitter taste receptors. <ref><pubmed>10761935</pubmed></ref>
[http://www.sciencedirect.com/science/article/pii/S0092867400807060 T2Rs Function as Bitter Taste Receptors]

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''2001'''
|Nelson, G. et al. discover the sweet receptor: a combination of T1R2 and T1R3. <ref><pubmed>11509186</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pubmed/11509186?dopt=Abstract&holding=npg Mammalian sweet taste receptors.]

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''2002'''
|Nelson G. et al. discover the amino acid (umami) taste receptor: a combination of T1R1 and T1R3 identified. <ref><pubmed>11894099</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pubmed/11894099?dopt=Abstract&holding=npg An amino-acid taste receptor]

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''2005'''
|Dyer, J. et al. discover sweet taste receptors in the GI tract. <ref><pubmed>17855558</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1986582/ Sweet taste signaling in the gut]

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''2006'''
|Huang, A. L et al. discover cells for sour taste, identified by PKD2L1 (a polycystic kidney disease-like ion channel). <ref><pubmed>16929298</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1571047/ The Cells and Logic for Mammalian Sour Taste detection]

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''2007'''
|Harlow DE, Barlow LA of the University of Colorado Denver Health Sciences Center provide evidence of the "embryonic origin of gustatory cranial sensory neurons". <ref name="PMID17826760"/>
[http://www.ncbi.nlm.nih.gov/pubmed/17826760 Embryonic origin of gustatory cranial sensory neurons.]

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''2009'''
|A study by Hevezi P et al, presents "the first comprehensive characterization of gene expression in primate taste buds", as opposed to previous studies which focused on rodents. <ref><pubmed>19636377</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pubmed/19636377 Genome-wide analysis of gene expression in primate taste buds reveals links to diverse processes]

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''2010'''
|Chandrashekar, J. et al. identify epithelial sodium channel (ENaC) as the sodium-salt taste receptor. <ref><pubmed>20107438</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pubmed/20107438?dopt=Abstract&holding=npg The cells and peripheral representation of sodium taste in mice]
|}

== Human Weekly Development - Two Prominent Studies ==
Martin Witt and Klaus Reutter of the University of Tubingen in Germany published two prominent studies regarding developing taste buds in humans. Their first study in 1996 was a transmission electron microscopical (TEM) study of the taste bud primordium and its morphological changes during the 8th-15th postovulatory week. Their next study in 1997 built on their previous findings by using Scanning Electron Microscopy (SEM) to observe the development of gustatory [[#Glossary |'''papillae''']] during postovulatory weeks 6-15.

The findings of these two studies are summarized in the table below. The figures provided relate to the images on their respective research papers.

# [http://onlinelibrary.wiley.com/doi/10.1002/(SICI)1097-0185(199612)246:4%3C507::AID-AR10%3E3.0.CO;2-S/pdf Embryonic and early fetal development of human taste buds: a transmission electron microscopical study, 1996]
# [http://chemse.oxfordjournals.org/content/22/6/601.long Scanning electron microscopical studies of developing gustatory papillae in humans, 1997]

===Timeline of Developmental Processes of Human Taste Buds===
{| cellpadding=5 style="border:1px solid #BBB"
|- bgcolor="#89CFF0"
|'''Postovulatory Week'''||'''Description'''

|- bgcolor="#BCD4E6"
|'''Week 6''' ||
The surface of the developing tongue is covered by nearly flat epithelium (1997, Figure 1). The first gustatory papillae of the tongue appear in the caudal mid-line near the foramen caecum and the first circumvallate papilla develops on the dorsal mid-line. <ref name="PMID9455607"><pubmed>9455607</pubmed></ref>

|- bgcolor="#89CFF0"
| '''Weeks 6 to 7'''||
Nerve fibers approach the basal lamina of lingual epithelium. At this stage the lingual epithelium consists of two to three cell layers and there is not yet any sign of cell specializations indicating early taste bud formation. <ref name=PMID8955790/>

|- bgcolor="#BCD4E6"
| '''Week 7 '''||
A series of irregular epithelial swellings in the anterior part and marginal parts of the tongue indicate early forming fungiform papillae. Furthermore, a V-like lane is observed anterior to the [[#Glossary |'''sulcus terminalis''']], which represents a smooth surface for developing circumvallate papillae (1997, Figure 2). Witt M et al observe that these circumvallate papillae are larger than the developing fungiform papillae of the same age, later noting that the fungiform papillae tend to increase in size over the 8-15th weeks of gestation, whilst the size of vallate papillae tend to remain constant during this period. <ref name=PMID9455607/>

|- bgcolor="#89CFF0"
| ''' Week 8 ''' ||
* The taste bud primordium are still differentiated, elongated epithelial cells, resting on a slightly developed core of young dermal papilla.
* The lingual epithelium shows first signs of taste bud development as nerve fibers coming from the dermal papilla penetrate the epithelial basal lamina and form synapses with taste bud progenitor cells (1996, Figure 1). These synapses demonstrate the neuronal connection between the taste bud primordium and the central nervous system, reaching a maximum around the 12th to 13th week. However, it is important to note that at this time these cells are still poorly differentiated, elongated epithelial cells.
* Ciliated cells also appear around the 8th week, however the significance of these cells which are scattered randomly across the lingual surface remains unclear. <ref name=PMID8955790/>

|- bgcolor="#BCD4E6"
|''' Week 9''' ||
By this stage, although a taste pore is not present, the surface of circumvallate papillae usually contains a taste pit partly filled with microvillus-like processes from the underlying taste bud cells (1997, Figure 10). <ref name=PMID9455607/>

|- bgcolor="#89CFF0"
|''' Weeks 10-11''' ||
At this stage, the lingual epithelium compromises of about four cell layers, and the first shallow grooves above the taste bud primordium are developed. Fungiform papillae appear on the lateral margins and the tip of the tongue, containing taste bud primordial that display the first signs of a primitive pore formation (1996, Figure 6). <ref name=PMID8955790/>

|- bgcolor="#BCD4E6"
|''' Week 12 ''' ||
Taste bud cells are more clearly differentiated into epithelial cell types II and III. <ref name=PMID8955790/>

|- bgcolor="#89CFF0"
|''' Weeks 12-13 ''' ||
At this stage the taste bud primordial are all located on the top of dermal papillae. There is also maximum synapses between cells and afferent nerve fibers, which intermingle with each other to form a plexus-like structure (1996, Figure 6a). <ref name=PMID8955790/>

|- bgcolor="#BCD4E6"
|''' Weeks 14 -15 ''' ||
The shape and size of the taste buds primordial begins to resemble those of adult taste buds (1996, Figure 9). By the 14th week the taste pores develop as the taste pits are filled by microvilli, and bubble like vesicles indicate the secretory activity of these cells (1996, Figure 10). However, the taste buds only achieve a fully developed function in week 15 of gestation with the development of type I cells to produce the mucous material in the taste pit. <ref name=PMID8955790/>
|}

==Abnormalities==

It should be mentioned that gustatory abnormalities have not been widely researched. Most research conducted in this field has been conducted through animal testing on mice and this is the basis of information provided below.

===Knocking out P2X Receptors===

[[File:Image of taste being evoked by visualising ATP release.jpeg|Left|thumb|200px|Evoking taste - ATP release in tongue]]

In Huang, 2008 this team used the release of the [[#Glossary |'''ectoderm''']], ATP (adenosine triphosphate) as a quantitative measurement of gustatory sensation and taste. This was done by using a comparison of wild type (WT) and double knockout (DKO) mice. P2X receptors, P2X2 and P2X3 were knocked out in the DKO mice. The premise of this article was that knocking out P2X receptors reduces transmitter secretion of ATP in taste buds, therefore they cannot taste.

It should be noted that the taste buds in DKO are functional, but are not stimulated by the administration of tastants.

The transmission of release of ATP is secretion through gap junction hemichannels (pannexin 1 gap junction).

When both P2X2 and P2X3 are knocked out, no taste is elicited. However they found that if either P2X2 OR P2X3 was knocked out there was a taste response. So the inference made from this is that if one of the two receptors from the P2X family was knocked out there still can have taste response. The WT mice showed significant stimulation by tastants whereas DKO had little to no stimulation of ATP release.<ref><pubmed>21940456</pubmed></ref>

===FGF signalling and genes===

Sprouty, or ''Srpy'', genes have been related to regulating the development of circumvallate papillae (CVP). The CVP are large dome shaped papillae, which form a 'V' just in front of the terminal sulcus.

By knocking out ''Spry'' genes using mice which had ''Spry1'' and ''Spry2'' knocked out showed that the number of CVP doubled. However, when Fibroblast [[#Glossary |'''Growth Factor''']] gene ("Fgf10") was absent, the number of CVP was significantly reduced, if not completely absent. The correlation between ''Spry1/2'' and ''Fgf10'' is that ''Spry1/2'' antagonizes "Fgf10" to limit the size of the CVP progenitor placode. Exclusive expression of ''Fgf10'' in the [[#Glossary |'''mesenchyme''']] is necessary for the formation of CVP.

'''This image shows the CVP stained with H&E and scanned by Scanning Electron Microscope (SEM)'''
[[File:CVP of WT(top) and DKO(bottom) mice with H&E and SEM.png]]

'''This image shows the location of the CVP and the increased number in DKO mice by SEM'''
[[File:Mouse circumvallate papilla 01.jpg|300px]]

Taste buds develop from the mesenchyme but require local signalling to properly differentiate. Some signalling factors for proper development of taste buds besides FGF are: [[#Glossary |'''Sonic Hedgehog''']] (SHH), Bone Morphogenetic Proteins (BMPs), Epidermal Growth Factor (EGF).

Additionally, this proves that the anterior and posterior developments of the tongue are derived from embryonic tissues, where the anterior tongue is derived from the [[#Glossary |'''ectoderm''']] and the posterior tongue is derived from the [[#Glossary |'''endoderm''']]. Taste buds develop from the mesenchyme but require local signalling to properly differentiate. Some signalling factors for proper development of taste buds besides FGF are: Sonic Hedgehog (SHH), Bone Morphogenetic Proteins (BMPs), Epidermal Growth Factor (EGF).

As mentioned above, this article shows that the anterior and posterior developments of the tongue are derived from embryonic tissues, where the anterior tongue is derived front the ectoderm and the posterior tongue is derived from the endoderm. Secondly, FGF is required to regulate the growth of taste buds, while ''Spry'' genes limit the number of CVP. ''Fgf10''& ''Spry 1&2''work antagonistically through receptor tyrosine kinase (RTK)signalling.

However, the deletion of ''Spry2''led to the increase of CVPs it should be noted that they found that a significant decrease in number of fungiform papillae. In contrast, the absence of ''Fgf10'', while leading to the absence of CVPs lead to an increase in number and size of fungiform papillae. Therefore these genes have different effects on the anterior and posterior developing tongue and taste buds.<ref><pubmed>21655085</pubmed></ref>

==Gustatory System==

[[Image:Taste qualities.gif|thumb|The five basic tastes]]

Taste or more appropriately gustation, is a fundamental survival tool in animals as it directs the consumption of essential nutrients. The five tastes that exist within the human gustatory system: salty, sweet, sour, bitter and umami, all signify basic physiological requirements. Salty tastes denote the presence of Na+, an important ion involved in the transportation and retention of water across cell membranes. Sweetness is the recognition of carbohydrates, essential for maintaining optimal brain function and providing the basis for energy production in muscle tissue via ATP [[#Glossary |'''hydrolysis''']]. Similarly umami codes for the presence of L-amino acids, especially L-glutamate which is an integral component of protein synthesis.

These different modalities not only function to maintain the proper intake of nutrients within the body but also, by way of aversion, prohibit the consumption of undesired or poisonous materials. The bitter modality for example is generally regarded as displeasing to the human palate. It represents a high acid content which may be a result of foods which have become rotten or are inherently poisonous to the body.<ref name=PMID20696704><pubmed>20696704</pubmed></ref>

Research has historically limited itself to investigating the mechanisms of these five taste qualities though it must be noted many other modalities may exist. Of particular conjecture is the existence of fatty acid recognition. In the past the detection of fat in food has been attributed to somatosensory inputs <ref name=PMID20696704/> from the tongue, that is, the oily feel and texture of fat rather than its actual ‘taste’ allows the brain to encode for its presence. Further research is therefore required to elicit the precise mechanisms of fat detection.

===Cell Biology===

The five taste qualities are not all detected by the same type of receptor cell located within the taste bud. Like rods and cones in the eye which detect different wavelengths of light, there are specific types of receptors for different tastes. For example, sweet, umami and bitter are recognized by Type II G-protein coupled receptors, whereas sour is related to Type III presynaptic cells. The cell type involved in salty taste transduction is unknown however it is known that sodium ions can enter the receptor cell membrane via ion channel permeation.

====Type II receptors====

When a bitter, sweet or umami ligand binds to a type II G-coupled receptor, a cascade of chemical reactions causes the release of Ca2+ which in turn mediates [[#Glossary |'''exocystosis''']] of ATP. The function of this ATP is threefold:

# Stimulates gustatory nerve afferents which project to gustatory nuclei in the spinal cord
# Excites Type III presynaptic nerve fibers to release serotonin.
# Has a positive feedback effect on type II receptor cells, increasing the level of ATP production.

The role of serotonin is believed to be in the form of lateral inhibition i.e. when a bitter quality is recognized, adjacent receptors for sweetness are deactivated and thus the two tastes may be clearly differentiated. It also has a negative feedback effect on receptor cells, inhibiting umami, bitter and sweet taste transduction.

==Taste Map==
[[Image:Taste map.png|thumb|left|250px|Obsolete idea of the tongue map]]
The idea of a tongue map has disseminated through society for many years. This concept purports that different areas of the tongue are specialized to detect either sweet, salty, sour and bitter tastes. Recent research however has completely nullified such claims and suggests instead that different forms of taste are recognized all over the tongue as well as via the palate. Thus the term ''taste map'' has come to take on a new meaning and that is, the precise areas of taste modalities processing in areas of cortex and its subsequent neural inputs.

===Neural Pathways===

'''First order [[#Glossary |'''neuron''']]''' - From the receptors located in the taste buds, gustatory nerve afferents project to the ipsilateral rostral 1/3 of the nucleus tractus solitarius (NTS), located in the medulla. This rostral 1/3 is commonly referred to as the ''gustatory nucleus''.

The ''gustatory nucleus'' receives input from cranial nerves VII (''Facial n.''), IX (''Hypglossal n.''), and X (''Vagus n.'') via special visceral afferent (SVA) nerve fibers. A summary of their functions is as follows:

* ''Facial nerve n''. - carries taste information from the anterior 2/3 of the tongue.
* ''Hypoglossal n.'' - carries taste information from the posterior 1/3 of the tongue.
* ''Vagus n''. - carries taste information from the palate

'''Second order neurons''' - From the NTS second order neurons carry taste information to the Ventral posteromedial (VPM) nucleus in the thalamus.<ref name=PMID21885776/>

Copious scientific conjecture surrounds how each taste modality is transmitted to the brain. The ‘labelled-line’ hypothesis suggests that there are taste specific neurons which exclusively carry that taste modality to cortical areas. In analogous terms it can be viewed like the pipelines leading toward a house. Each pipeline carries its own utility, there is one for gas, another for water and finally for electricity with each terminating in slightly different areas of the house. In the same way, on the tongues there are different receptors for each taste which concurrently have individual nerve tracts leading to the primary gustatory cortex.

Contrapuntally there is electrophysiological evidence that single nerve afferents carry multiple modalities. These studies show one nerve afferent may have both a strong and a weak activation in response to a multiple taste stimuli.

===Cortical Areas===

[[Image:Primary gustatory cortex.png|thumb|Primary gustatory cortex]]

The location of the taste perception centers has been observed via functional magnetic resonance imaging (fMRI) studies. The primary taste cortex has been identified as being located in the anterior insula/frontal operculum (I/fO)<ref name=PMID22245354><pubmed>22245354</pubmed></ref>, with the secondary taste cortex in the caudolateral orbitofrontal cortex.<ref name=PMID21305668><pubmed>21305668</pubmed></ref> Within the insula there are further subdivisions related to each taste modality. Two photon calcium imaging research has outlined certain ’hot-spots’ of activation which are clearly delineated in relation to each taste. For example, the bitter modality is represented on the insula cortex approximately 1mm posterior to the middle cerebral artery whereas the sweet modality is represented 2.5mm rostrodorsal to the bitter field with no apparent overlap.<ref name=PMID21885776><pubmed>21885776</pubmed></ref> These findings lend weight to the idea that there is only one receptor for each taste quality.

It is interesting to note the relationship between taste and the reward centers of the brain. There is evidence of neural input to the ventral tegmental area (the origin of the mesolimbic dopaminergic reward pathway) and nucleus accumbens (involved in the conversion of motivation into physical action).<ref name=PMID21885776/> Neural connections such as this provide the foundations in explaining concepts such as flavour learning and preference. It may also give some insight into chronic problems such as food addiction and craving. As of yet however the gustatory neural network is not well understood and more research is required to elucidate the relationship between pleasure and taste sensation

===Neuronal Development===

The gustatory system must not be solely thought of as being comprised of simply the tongue and palate. The types of neurons which carry taste information to the brain are also pivotal in constructing the expression of taste qualities.

The two main gustatory neurons which develop are the geniculate ganglion and the petrosal ganglion. These are the visceral sensory ganglion of cranial nerves VII (Facial) and IX (Hypoglossal) respectively which carry taste information from the tongue to the nucleus tractus solitarius. They arise at the posterior placodal region from the epibranchial placodes, a thickening of ectoderm. The first epibranchial placode gives rise to the geniculate ganglion and the second to the petrosal ganglion.

The molecular basis for gustatory neuron formation is not completely understood though there are a number of transcription factors which are thought to play an important role in firstly, placode formation and secondly, neuron differentiation.

*Six1/2, Six1/5 and Eya – transcription factors which cause differentiation of epibranchial placodes into the petrosal and geniculate ganglion.
*Bone morphogenic Protein 7 (BMP7) – a signal arising from the pharyngeal pouch which is believed to induce epibranchial placode formation. May not be solely responsible for this process, current research has been inconclusive as to how it may work with other proteins of the same family.
*NGN2 - Following the initial differentiation of the placodes, further differentiation occurs to form neuroblasts. NGN2 causes the delamination and migration of these neuroblasts, which subsequently migrate and fuse to form neurons.
*Phox2b – maintains the structural integrity of neurons. Knockout of these genes in mice causes marked atrophy of the petrosal and geniculate ganglia.

The neurons involved in the gustatory system are overproduced and thus in the embryonic stage, undergo programmed cell death (apoptosis). The total amount of neurons in the geniculate ganglion, appears to be quite stable over the embryonic stages. This suggests, unlike the petrosal ganglion, the levels of neuroblast proliferation and apoptosis are fairly similar. The factors which regulate these processes remains unclear. It is posited that neurotrophins BDNF, NT4/5 and NT3 may regulate neuronal survival whilst also playing a part in axon growth from the sensory ganglion. More research is required to discern the exact individual functions of each of the neurotrophins.

==Current Research==

[[File:Mousetounge histologicalstain.jpg|right|thumb|200px|Image shows histological stains of a mice tongue showing dysplasia]]

We have an evolving understanding of Embryonic Taste development, through the use of state-of-the-art technology and research techniques we are able to make brilliant discoveries that continue to connect the dots of this amazing natural process of human development.
The majority of research in taste development is involving mice, these mammals show similar embryonic pathways to humans and research is performed in ethical and humane methods.

'''Synergistic relationships of Six Genes '''

In an animal study using mice by Suzuki Y, Ikeda K, Kawakami K.(2011) Firstly nominating "[[#Glossary |'''Six Genes''']]" as a major component in [[#Glossary |'''gustatory ''']] development, stating that deficiencies in certain Six genes (specifically Six1 & Six4) leads to poor development. Their research also highlights evidence of cooperative relationships between Six genes for normal advance. This experiment involved breeding mice containing exclusively Six1 and Six4 genes and examining the expression of these genes in papillae under high powered microscope observation. Understanding the role of certain genes along with the intrinsic relationships they hold is crucial for the ability to identify possible causes and correction of any abnormalities <ref><pubmed>21978088</pubmed></ref>

[[File:Highpowered_microscope.jpg|Left|thumb|200px|Image of a high powered microscope]]

'''Neural Crest responsibilities '''

Another Animal Study involving mice explores a new idea of [[#Glossary |'''Neural crest''']] (NC) contribution in taste development, specifically the development of papillae and taste buds. Liu HX, Komatsu Y, Mishina Y, Mistretta CM. (2012) suggest that Neural crest cells travel to the location of the tongue in early embryonic stages, gain epithelium phenotypes, multiply and then differentiate to eventually form taste papillae. The experiment involved the comparison of 2 different types of Cre line mice, which both express Cre gene in neural crest protocol, the different distribution patterns where observed in specific regions that NC is responsible for.<ref><pubmed>22659543</pubmed></ref>

'''Augmentation of Endoderm'''

In an animal study conducted by Rothova M, Thompson H, Lickert H, Tucker AS.(2012) exploring the historically debated issue of endoderm contribution to tongue development showed promising evidence that position of taste buds are patterned by the border of ectoderm and endoderm derivative epithelium. This study was accomplished via microscopic examination of previously stained specimens. Concluding endoderm has direct influence on gustatory development <ref><pubmed>22581563</pubmed></ref>

'''Changes in Taste Cells over time'''

Research by
Ozdener H, Spielman AI, Rawson NE.(2012) developing a culture which allows taste cells to survive for up to 12 months, empowers researchers to study the processes of proliferation, differentiation and function. This experiment will provide a precedent for future study of taste cells, as these cells are able to operate and grow normally. <ref><pubmed>22643728</pubmed></ref>

'''Shh key component of taste bud proginators'''

A [[#Glossary |'''tamoxifen''']] treatment which suppresses Sonic hedgehog (Shh) secretion in mice proving to reduce the number of cells visible within papillae, in contrast mice not treated with tamoxifen showed a mark increase of cells within papillae, these cells are assumed to become taste cells in later development.
Specific mice were bred to trace the destination of taste placode cells, the study concluded that Shh expressing placodes are taste bud proginators which in turn become taste cells within taste buds although do not have any precursors relationship with papillae. The results were obtain by examination of mice embryos using Bright-field or multichannel fluorescent images through the use of an "Axiocam CCD camera and Axioplan fluorescence microscope with Axiovision software" a study by Harlow, Yang, Williams, Barlow (2011)<ref><pubmed>PMC2674259</pubmed></ref>

'''WNT family exhibit various roles'''

[[File:Abnormal of tongue.jpg|thumb|200px|Image shows an example of tongue abnormalities, this is called "double tongue" each side has independent movement!]]

The WNT gene family has a function of signaling work antagonistically through receptor tyrosine kinase (RTK) signaling. However, the deletion of Sprouty Homolog 2 (Spry2) led to the increase of chimaeric virus particles (CVPs) and a significant decrease in number of fungiform papillae. In contrast, the absence of Fibroblast growth factor 10 (Fgf10) in conjunction with absence of CVPs lead to an increase in number and size of fungiform papillae. Therefore these genes have different effects on the anterior and posterior developing tongue and taste buds. In 2010 Liu, Staubach Grosse, Walton, Saims, Gumucio, Mistretta explored recent findings on the role of WNT's in tongue and papillae development, Concluding that WNT/β-catenin is essential for fungiform papillae differing to WNT5a which proved to be principle in tongue development. Intrinsic chemical mediators were considered by manipulating a tissue culture and then thoroughly examined by scanning photomicrograph. <ref><pubmed>PMC2768563</pubmed></ref>

[[File:Developing_tongue_histology_001.jpg|right|thumb|200px|HIstological stain of a developing rat tongue]]

==Glossary==

* '''Circumvallate papillae''' -

* '''Ectoderm'''- outer germ layer of embryo

* '''Endoderm''' - inner germ layer of embryo

* '''Epithelium''' - basic animal tissue that is composed of tightly packed cells, usually covering the outer portion of organs

* '''Exocystosis''' - movement of contents out of cell

* '''Filiform papillae''' -

* '''Foliate papillae''' -

* '''Fungiform papillae''' -

* '''Ganglia''' - the accumulation of a nerve cell body

* '''Growth factor''' - a substance that stimulates the growth of cells

* '''Gustatory''' - anything that relates to the taste sense

* '''Hydrolysis''' - breakdown of a chemical when it reacts with water

* '''Mesoderm''' - middle germ layer of embryo

* '''Mesenchyme''' - multipotential cells

* '''Neural crest''' - a part of the ectoderm found on both sides of the neural tube

* '''Neuron''' - most simplistic unit of the nervous system

* '''Neurotransmitter''' - chemicals which allow the passing of signals from neuron to neuron via connecting part (synapse)

* '''Papillae''' - small rough surface projection

* '''Six genes''' - a family of genes

* '''Sonic hedgehog (Shh)''' - signalling protein involved in normal development

* '''Sulcus terminalis''' - describes a physical transition point separating the anterior 2/3 of the tongue from the posterior 1/3

* '''Tamoxifen''' - hormonal altering drug

* '''Type I taste cells''' - The most abundant cells in taste buds; involved in terminating synaptic transmissions (similar to the role of glial cells in the CNS).

* '''Type II taste cells''' - Receptor cells acting as primary detectors of sweet, bitter or umami taste.

* '''Type III taste cells''' - Presynaptic cells that respond to sweet, salty, sour, bitter and umami compounds.

== References ==
<references/>

==External Links==
{{External Links}}

[http://www.surgicalneurologyint.com/article.asp?issn=2152-7806;year=2012;volume=3;issue=1;spage=23;epage=23;aulast=Manjila]

http://embryology.med.unsw.edu.au/embryology/index.php?title=2012_Group_Project_4

http://www.webmd.com/oral-health/picture-of-the-tongue

http://www.tutorvista.com/content/biology/biology-iv/nervous-coordination/tongue-structure.php#parts-of-tongue

http://www.cf.ac.uk/biosi/staffinfo/jacob/teaching/sensory/taste.html

--[[User:Z8600021|Mark Hill]] 12:22, 15 August 2012 (EST) Please leave the content listed below the line at the bottom of your project page.

----

{{2012Projects}}

2012 Group Project 3

2012-10-02T05:21:16Z

Z3330986: /* Taste Development */

=Taste Development=

You are out to dinner and your meal arrives in front of you, the aromas and the presentation of your food strikes you immediately. Half way through, the waiter returns and asks “How does your meal taste?” The answer is not as simple as one might think. Why does the meal taste pleasant? How do we experience different tastes? In the following page, we aim to discern how exactly one would answer these questions by looking at the embryological development of the taste system from week to week.

Taste is a complex sensory system and its precise workings are to this day not fully understood. What makes it so complicated is the interaction between the structure of tongue and taste buds and how this contributes to the representation of taste qualities (salty, bitter, sweet, sour and umami) in the brain. We will also look at some current research on animal models being undertaken to evaluate the role of specific genes in the development of sensory structures. By looking at the taste system’s genetic basis, we now have a greater understanding of the abnormalities that may occur during development and a direction to pursue in future research to attempt to fill in the gaps of scientific knowledge.

==Adult Tongue and Taste Buds – Structure and Function==

'''Structure'''

The tongue is located on the floor of the oral cavity, It is a muscular structure with sensory units crowning. The tongue is divided into an anterior two thirds and a posterior one third. These regions are divided by a V-shaped groove at the back of the tongue (sulcus terminalis). The anterior two thirds of the tongue is covered by stratified squamous epithelium, It contains a roughened surface and has projections called papillae that vary in shape and number.

''''The image below is a simplistic diagram of the surface of the tongue showing the locations of the different papillae and other important features'''

{|
| [[Image:Drawing of Tongue.png|centre|500px]]

'''Papillae'''
[[File:Papillae.jpg|Left|thumb|200px|Close up of Human Tongue Papillae]]

There are 4 types of papillae on the tongue.
The most numerous papillae are the filiform papillae, which function to provide a surface that aids in holding food on the tongue during chewing but do not contain taste buds. The larger, less numerous fungiform papillae which contain taste buds, as do foliate papillae. Circumvallate papillae form a wide V at the sulcus terminalis also containing taste bus. There are no papillae or taste buds located on the posterior third of the tongue, having mucosal folds and the lingual tonsils instead.

[[File:Fungiformpapillae.jpg|Left|thumb|200px|Fungiform Papillae]]

[[File:Circumvallatepapillae.jpg |Left|thumb|200px|Circumvallate Papillae]]

[[File:Filiformpapillae.jpg|Left|thumb|200px|Foliate Papillae]]

'''Function'''

The Tongue has muscular and sensory functions, muscular functions include swallowing and speech where as sensory function involves taste. This section will focus on the sensory functions of the tongue.
The functional unit of the taste bud is a taste cell, there are between 50 and 100 taste cells in each taste bud these taste cells represent all 5 different tastes. Historically is was believed that different areas of the tongue were responsible for different taste sensations although this has since been disregarded.[http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/W/Welcome.html] The papillae contain taste buds which are connected to the oral cavity via a taste pore, the function of the taste bud is to transmit a chemical signal from the oral cavity to a taste cell, this chemical signal is the converted into an electrical impulse and delivered to the brain via nerve fibres for interpretation.

'''The image below is a simplistic hand-drawn cross section of a taste bud unit (not to scale)'''

[[File:Taste_bud_1.jpg|x400px|alt=Cross section of a taste bud unit|centre|Cross section of a taste bud unit]]

'''Link Between Taste and Smell'''

The pathways between smell and taste are very similar. Pathways both involve the conversion of a chemical stimulus into a nerve impulse for interpretation by the brain. People often mistake taste for flavour, flavour involves an interaction of taste, smell, texture and temperature.
When there is food in our mouth there is signalling between these senses giving a whole package interpretation instead of just taste itself, the communication of these senses allows an indvidual a more specific perception of what they are eating.
[http://serendip.brynmawr.edu/exchange/node/1575]

[[File:Taste_pathway.jpg|right|thumb|200px|Simplistic Pathway of Taste]]

[[File:Human smelling.jpg|500px|centre]]

==History of Discoveries==

{| cellpadding=5 style="border:1px solid #BBB"
|- bgcolor="#faecc8"
|''' Date'''|| '''Significant Discovery'''

|- bgcolor="#faf6ed"
|'''350BC'''
|| Aristotle writes about the basic tastes, sweet and bitter. He also notes that it can be modified by salty and acidic. <ref name="PMID22717400"><pubmed>22717400</pubmed></ref>

|- bgcolor="#faecc8"
|'''1901'''
|| D. Hanig publishes a paper describing taste sensitivity in different regions of the tongue.
''Interesting fact:'' The modern concept of a 'tongue map' is a misinterpretation of this study. <ref name="PMID22717400"/>

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''1908'''
|Kikunae Ikeda, a professor of the Tokyo Imperial University, discovered and identified the fifth basic taste: umami (savouriness), made palatable by glutamate. <ref><pubmed>12438213</pubmed></ref>
[http://chemse.oxfordjournals.org/content/27/9/847.long New Seasonings]

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''1931-32'''
| A chemist named Arthur Fox and his college noted that they had different sensitivities to the bitter tasting Phenylthiocarbamide (PTC).<ref>Blakeslee AF, Fox AL. Our different taste worlds. J Hered. 1932;23:97–107.</ref> Geneticists later confirm these findings, and discover that non-tasting is a recessive genetic trait. <ref><pubmed>17782493</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pubmed/17782493 Inherited taste deficiency]

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''1965'''
|Farbman's study of the developing taste but in rat fungiform papilla was significant in increasing our understanding of taste bud development. <ref><pubmed>14300090</pubmed></ref>
[http://www.sciencedirect.com/science/article/pii/0012160665900400 Electron microscope study of the developing taste bud in rat fungiform papilla.]

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''1992'''
|McLaughlin SK et al. discovery a taste cell-specific G-protein within the taste buds called Gustucon. This protein is later used to mark bitter, umami and sweet cells. <ref><pubmed>1608467 </pubmed></ref>
[http://www.nature.com/nature/journal/v357/n6379/abs/357563a0.html Gustducin is a taste-cell-specific G protein closely related to the transducins]

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''1995'''
|Barlow et al. experimented with Axolotl salamanders and concluded that taste buds from this species arise exclusively from epithelial tissue, "oropharyngeal [[#Glossary |'''epithelium''']]". <ref name="PMID17826760"><pubmed>17826760</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pubmed/17826760 Embryonic origin of gustatory cranial sensory neurons]

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''1996'''
| Witt M and Reutter K of the Technical University Dresden in Germany, carried out a transmission electron microscopy study to investigate the embryonic and fetal development of Human taste buds. Their results suggest an "at least dual function of embryonic/fetal taste buds", including non-gustatory, paracrine functions prior to the 14th week and gustatory after the 14th week. <ref name="PMID8955790"><pubmed>8955790</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pubmed/8955790 Embryonic and early fetal development of human taste buds: a transmission electron microscopical study]

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''2000'''
|Chandrashekar, J. et al. discover the first taste sonsors, the T2R bitter taste receptors. <ref><pubmed>10761935</pubmed></ref>
[http://www.sciencedirect.com/science/article/pii/S0092867400807060 T2Rs Function as Bitter Taste Receptors]

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''2001'''
|Nelson, G. et al. discover the sweet receptor: a combination of T1R2 and T1R3. <ref><pubmed>11509186</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pubmed/11509186?dopt=Abstract&holding=npg Mammalian sweet taste receptors.]

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''2002'''
|Nelson G. et al. discover the amino acid (umami) taste receptor: a combination of T1R1 and T1R3 identified. <ref><pubmed>11894099</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pubmed/11894099?dopt=Abstract&holding=npg An amino-acid taste receptor]

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''2005'''
|Dyer, J. et al. discover sweet taste receptors in the GI tract. <ref><pubmed>17855558</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1986582/ Sweet taste signaling in the gut]

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''2006'''
|Huang, A. L et al. discover cells for sour taste, identified by PKD2L1 (a polycystic kidney disease-like ion channel). <ref><pubmed>16929298</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1571047/ The Cells and Logic for Mammalian Sour Taste detection]

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''2007'''
|Harlow DE, Barlow LA of the University of Colorado Denver Health Sciences Center provide evidence of the "embryonic origin of gustatory cranial sensory neurons". <ref name="PMID17826760"/>
[http://www.ncbi.nlm.nih.gov/pubmed/17826760 Embryonic origin of gustatory cranial sensory neurons.]

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''2009'''
|A study by Hevezi P et al, presents "the first comprehensive characterization of gene expression in primate taste buds", as opposed to previous studies which focused on rodents. <ref><pubmed>19636377</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pubmed/19636377 Genome-wide analysis of gene expression in primate taste buds reveals links to diverse processes]

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''2010'''
|Chandrashekar, J. et al. identify epithelial sodium channel (ENaC) as the sodium-salt taste receptor. <ref><pubmed>20107438</pubmed></ref>
[http://www.ncbi.nlm.nih.gov/pubmed/20107438?dopt=Abstract&holding=npg The cells and peripheral representation of sodium taste in mice]
|}

== Human Weekly Development - Two Prominent Studies ==
Martin Witt and Klaus Reutter of the University of Tubingen in Germany published two prominent studies regarding developing taste buds in humans. Their first study in 1996 was a transmission electron microscopical (TEM) study of the taste bud primordium and its morphological changes during the 8th-15th postovulatory week. Their next study in 1997 built on their previous findings by using Scanning Electron Microscopy (SEM) to observe the development of gustatory [[#Glossary |'''papillae''']] during postovulatory weeks 6-15.

The findings of these two studies are summarized in the table below. The figures provided relate to the images on their respective research papers.

# [http://onlinelibrary.wiley.com/doi/10.1002/(SICI)1097-0185(199612)246:4%3C507::AID-AR10%3E3.0.CO;2-S/pdf Embryonic and early fetal development of human taste buds: a transmission electron microscopical study, 1996]
# [http://chemse.oxfordjournals.org/content/22/6/601.long Scanning electron microscopical studies of developing gustatory papillae in humans, 1997]

===Timeline of Developmental Processes of Human Taste Buds===
{| cellpadding=5 style="border:1px solid #BBB"
|- bgcolor="#89CFF0"
|'''Postovulatory Week'''||'''Description'''

|- bgcolor="#BCD4E6"
|'''Week 6''' ||
The surface of the developing tongue is covered by nearly flat epithelium (1997, Figure 1). The first gustatory papillae of the tongue appear in the caudal mid-line near the foramen caecum and the first circumvallate papilla develops on the dorsal mid-line. <ref name="PMID9455607"><pubmed>9455607</pubmed></ref>

|- bgcolor="#89CFF0"
| '''Weeks 6 to 7'''||
Nerve fibers approach the basal lamina of lingual epithelium. At this stage the lingual epithelium consists of two to three cell layers and there is not yet any sign of cell specializations indicating early taste bud formation. <ref name=PMID8955790/>

|- bgcolor="#BCD4E6"
| '''Week 7 '''||
A series of irregular epithelial swellings in the anterior part and marginal parts of the tongue indicate early forming fungiform papillae. Furthermore, a V-like lane is observed anterior to the [[#Glossary |'''sulcus terminalis''']], which represents a smooth surface for developing circumvallate papillae (1997, Figure 2). Witt M et al observe that these circumvallate papillae are larger than the developing fungiform papillae of the same age, later noting that the fungiform papillae tend to increase in size over the 8-15th weeks of gestation, whilst the size of vallate papillae tend to remain constant during this period. <ref name=PMID9455607/>

|- bgcolor="#89CFF0"
| ''' Week 8 ''' ||
* The taste bud primordium are still differentiated, elongated epithelial cells, resting on a slightly developed core of young dermal papilla.
* The lingual epithelium shows first signs of taste bud development as nerve fibers coming from the dermal papilla penetrate the epithelial basal lamina and form synapses with taste bud progenitor cells (1996, Figure 1). These synapses demonstrate the neuronal connection between the taste bud primordium and the central nervous system, reaching a maximum around the 12th to 13th week. However, it is important to note that at this time these cells are still poorly differentiated, elongated epithelial cells.
* Ciliated cells also appear around the 8th week, however the significance of these cells which are scattered randomly across the lingual surface remains unclear. <ref name=PMID8955790/>

|- bgcolor="#BCD4E6"
|''' Week 9''' ||
By this stage, although a taste pore is not present, the surface of circumvallate papillae usually contains a taste pit partly filled with microvillus-like processes from the underlying taste bud cells (1997, Figure 10). <ref name=PMID9455607/>

|- bgcolor="#89CFF0"
|''' Weeks 10-11''' ||
At this stage, the lingual epithelium compromises of about four cell layers, and the first shallow grooves above the taste bud primordium are developed. Fungiform papillae appear on the lateral margins and the tip of the tongue, containing taste bud primordial that display the first signs of a primitive pore formation (1996, Figure 6). <ref name=PMID8955790/>

|- bgcolor="#BCD4E6"
|''' Week 12 ''' ||
Taste bud cells are more clearly differentiated into epithelial cell types II and III. <ref name=PMID8955790/>

|- bgcolor="#89CFF0"
|''' Weeks 12-13 ''' ||
At this stage the taste bud primordial are all located on the top of dermal papillae. There is also maximum synapses between cells and afferent nerve fibers, which intermingle with each other to form a plexus-like structure (1996, Figure 6a). <ref name=PMID8955790/>

|- bgcolor="#BCD4E6"
|''' Weeks 14 -15 ''' ||
The shape and size of the taste buds primordial begins to resemble those of adult taste buds (1996, Figure 9). By the 14th week the taste pores develop as the taste pits are filled by microvilli, and bubble like vesicles indicate the secretory activity of these cells (1996, Figure 10). However, the taste buds only achieve a fully developed function in week 15 of gestation with the development of type I cells to produce the mucous material in the taste pit. <ref name=PMID8955790/>
|}

==Abnormalities==

It should be mentioned that gustatory abnormalities have not been widely researched. Most research conducted in this field has been conducted through animal testing on mice and this is the basis of information provided below.

===Knocking out P2X Receptors===

[[File:Image of taste being evoked by visualising ATP release.jpeg|Left|thumb|200px|Evoking taste - ATP release in tongue]]

In Huang, 2008 this team used the release of the [[#Glossary |'''ectoderm''']], ATP (adenosine triphosphate) as a quantitative measurement of gustatory sensation and taste. This was done by using a comparison of wild type (WT) and double knockout (DKO) mice. P2X receptors, P2X2 and P2X3 were knocked out in the DKO mice. The premise of this article was that knocking out P2X receptors reduces transmitter secretion of ATP in taste buds, therefore they cannot taste.

It should be noted that the taste buds in DKO are functional, but are not stimulated by the administration of tastants.

The transmission of release of ATP is secretion through gap junction hemichannels (pannexin 1 gap junction).

When both P2X2 and P2X3 are knocked out, no taste is elicited. However they found that if either P2X2 OR P2X3 was knocked out there was a taste response. So the inference made from this is that if one of the two receptors from the P2X family was knocked out there still can have taste response. The WT mice showed significant stimulation by tastants whereas DKO had little to no stimulation of ATP release.<ref><pubmed>21940456</pubmed></ref>

===FGF signalling and genes===

Sprouty, or ''Srpy'', genes have been related to regulating the development of circumvallate papillae (CVP). The CVP are large dome shaped papillae, which form a 'V' just in front of the terminal sulcus.

By knocking out ''Spry'' genes using mice which had ''Spry1'' and ''Spry2'' knocked out showed that the number of CVP doubled. However, when Fibroblast [[#Glossary |'''Growth Factor''']] gene ("Fgf10") was absent, the number of CVP was significantly reduced, if not completely absent. The correlation between ''Spry1/2'' and ''Fgf10'' is that ''Spry1/2'' antagonizes "Fgf10" to limit the size of the CVP progenitor placode. Exclusive expression of ''Fgf10'' in the [[#Glossary |'''mesenchyme''']] is necessary for the formation of CVP.

'''This image shows the CVP stained with H&E and scanned by Scanning Electron Microscope (SEM)'''
[[File:CVP of WT(top) and DKO(bottom) mice with H&E and SEM.png]]

'''This image shows the location of the CVP and the increased number in DKO mice by SEM'''
[[File:Mouse circumvallate papilla 01.jpg|300px]]

Taste buds develop from the mesenchyme but require local signalling to properly differentiate. Some signalling factors for proper development of taste buds besides FGF are: [[#Glossary |'''Sonic Hedgehog''']] (SHH), Bone Morphogenetic Proteins (BMPs), Epidermal Growth Factor (EGF).

Additionally, this proves that the anterior and posterior developments of the tongue are derived from embryonic tissues, where the anterior tongue is derived from the [[#Glossary |'''ectoderm''']] and the posterior tongue is derived from the [[#Glossary |'''endoderm''']]. Taste buds develop from the mesenchyme but require local signalling to properly differentiate. Some signalling factors for proper development of taste buds besides FGF are: Sonic Hedgehog (SHH), Bone Morphogenetic Proteins (BMPs), Epidermal Growth Factor (EGF).

As mentioned above, this article shows that the anterior and posterior developments of the tongue are derived from embryonic tissues, where the anterior tongue is derived front the ectoderm and the posterior tongue is derived from the endoderm. Secondly, FGF is required to regulate the growth of taste buds, while ''Spry'' genes limit the number of CVP. ''Fgf10''& ''Spry 1&2''work antagonistically through receptor tyrosine kinase (RTK)signalling.

However, the deletion of ''Spry2''led to the increase of CVPs it should be noted that they found that a significant decrease in number of fungiform papillae. In contrast, the absence of ''Fgf10'', while leading to the absence of CVPs lead to an increase in number and size of fungiform papillae. Therefore these genes have different effects on the anterior and posterior developing tongue and taste buds.<ref><pubmed>21655085</pubmed></ref>

==Gustatory System==

[[Image:Taste qualities.gif|thumb|The five basic tastes]]

Taste or more appropriately gustation, is a fundamental survival tool in animals as it directs the consumption of essential nutrients. The five tastes that exist within the human gustatory system: salty, sweet, sour, bitter and umami, all signify basic physiological requirements. Salty tastes denote the presence of Na+, an important ion involved in the transportation and retention of water across cell membranes. Sweetness is the recognition of carbohydrates, essential for maintaining optimal brain function and providing the basis for energy production in muscle tissue via ATP [[#Glossary |'''hydrolysis''']]. Similarly umami codes for the presence of L-amino acids, especially L-glutamate which is an integral component of protein synthesis.

These different modalities not only function to maintain the proper intake of nutrients within the body but also, by way of aversion, prohibit the consumption of undesired or poisonous materials. The bitter modality for example is generally regarded as displeasing to the human palate. It represents a high acid content which may be a result of foods which have become rotten or are inherently poisonous to the body.<ref name=PMID20696704><pubmed>20696704</pubmed></ref>

Research has historically limited itself to investigating the mechanisms of these five taste qualities though it must be noted many other modalities may exist. Of particular conjecture is the existence of fatty acid recognition. In the past the detection of fat in food has been attributed to somatosensory inputs <ref name=PMID20696704/> from the tongue, that is, the oily feel and texture of fat rather than its actual ‘taste’ allows the brain to encode for its presence. Further research is therefore required to elicit the precise mechanisms of fat detection.

===Cell Biology===

The five taste qualities are not all detected by the same type of receptor cell located within the taste bud. Like rods and cones in the eye which detect different wavelengths of light, there are specific types of receptors for different tastes. For example, sweet, umami and bitter are recognized by Type II G-protein coupled receptors, whereas sour is related to Type III presynaptic cells. The cell type involved in salty taste transduction is unknown however it is known that sodium ions can enter the receptor cell membrane via ion channel permeation.

====Type II receptors====

When a bitter, sweet or umami ligand binds to a type II G-coupled receptor, a cascade of chemical reactions causes the release of Ca2+ which in turn mediates [[#Glossary |'''exocystosis''']] of ATP. The function of this ATP is threefold:

# Stimulates gustatory nerve afferents which project to gustatory nuclei in the spinal cord
# Excites Type III presynaptic nerve fibers to release serotonin.
# Has a positive feedback effect on type II receptor cells, increasing the level of ATP production.

The role of serotonin is believed to be in the form of lateral inhibition i.e. when a bitter quality is recognized, adjacent receptors for sweetness are deactivated and thus the two tastes may be clearly differentiated. It also has a negative feedback effect on receptor cells, inhibiting umami, bitter and sweet taste transduction.

==Taste Map==
[[Image:Taste map.png|thumb|left|250px|Obsolete idea of the tongue map]]
The idea of a tongue map has disseminated through society for many years. This concept purports that different areas of the tongue are specialized to detect either sweet, salty, sour and bitter tastes. Recent research however has completely nullified such claims and suggests instead that different forms of taste are recognized all over the tongue as well as via the palate. Thus the term ''taste map'' has come to take on a new meaning and that is, the precise areas of taste modalities processing in areas of cortex and its subsequent neural inputs.

===Neural Pathways===

'''First order [[#Glossary |'''neuron''']]''' - From the receptors located in the taste buds, gustatory nerve afferents project to the ipsilateral rostral 1/3 of the nucleus tractus solitarius (NTS), located in the medulla. This rostral 1/3 is commonly referred to as the ''gustatory nucleus''.

The ''gustatory nucleus'' receives input from cranial nerves VII (''Facial n.''), IX (''Hypglossal n.''), and X (''Vagus n.'') via special visceral afferent (SVA) nerve fibers. A summary of their functions is as follows:

* ''Facial nerve n''. - carries taste information from the anterior 2/3 of the tongue.
* ''Hypoglossal n.'' - carries taste information from the posterior 1/3 of the tongue.
* ''Vagus n''. - carries taste information from the palate

'''Second order neurons''' - From the NTS second order neurons carry taste information to the Ventral posteromedial (VPM) nucleus in the thalamus.<ref name=PMID21885776/>

Copious scientific conjecture surrounds how each taste modality is transmitted to the brain. The ‘labelled-line’ hypothesis suggests that there are taste specific neurons which exclusively carry that taste modality to cortical areas. In analogous terms it can be viewed like the pipelines leading toward a house. Each pipeline carries its own utility, there is one for gas, another for water and finally for electricity with each terminating in slightly different areas of the house. In the same way, on the tongues there are different receptors for each taste which concurrently have individual nerve tracts leading to the primary gustatory cortex.

Contrapuntally there is electrophysiological evidence that single nerve afferents carry multiple modalities. These studies show one nerve afferent may have both a strong and a weak activation in response to a multiple taste stimuli.

===Cortical Areas===

[[Image:Primary gustatory cortex.png|thumb|Primary gustatory cortex]]

The location of the taste perception centers has been observed via functional magnetic resonance imaging (fMRI) studies. The primary taste cortex has been identified as being located in the anterior insula/frontal operculum (I/fO)<ref name=PMID22245354><pubmed>22245354</pubmed></ref>, with the secondary taste cortex in the caudolateral orbitofrontal cortex.<ref name=PMID21305668><pubmed>21305668</pubmed></ref> Within the insula there are further subdivisions related to each taste modality. Two photon calcium imaging research has outlined certain ’hot-spots’ of activation which are clearly delineated in relation to each taste. For example, the bitter modality is represented on the insula cortex approximately 1mm posterior to the middle cerebral artery whereas the sweet modality is represented 2.5mm rostrodorsal to the bitter field with no apparent overlap.<ref name=PMID21885776><pubmed>21885776</pubmed></ref> These findings lend weight to the idea that there is only one receptor for each taste quality.

It is interesting to note the relationship between taste and the reward centers of the brain. There is evidence of neural input to the ventral tegmental area (the origin of the mesolimbic dopaminergic reward pathway) and nucleus accumbens (involved in the conversion of motivation into physical action).<ref name=PMID21885776/> Neural connections such as this provide the foundations in explaining concepts such as flavour learning and preference. It may also give some insight into chronic problems such as food addiction and craving. As of yet however the gustatory neural network is not well understood and more research is required to elucidate the relationship between pleasure and taste sensation

==Current Research==
We have an evolving understanding of Embryonic Taste development, through the use of state-of-the-art technology and research techniques we are able to make brilliant discoveries that continue to connect the dots of this amazing natural process of human development.
The majority of research in taste development is involving mice, these mammals show similar embryonic pathways to humans and research is performed in ethical and humane methods.

[[File:Mousetounge histologicalstain.jpg|Left|thumb|200px|Image shows histological stains of a mice tongue showing dysplasia]]

'''Synergistic relationships of Six Genes '''

In an animal study using mice by Suzuki Y, Ikeda K, Kawakami K.(2011) Firstly nominating "[[#Glossary |'''Six Genes''']]" as a major component in [[#Glossary |'''gustatory ''']] development, stating that deficiencies in certain Six genes (specifically Six1 & Six4) leads to poor development. Their research also highlights evidence of cooperative relationships between Six genes for normal advance. This experiment involved breeding mice containing exclusively Six1 and Six4 genes and examining the expression of these genes in papillae under high powered microscope observation. Understanding the role of certain genes along with the intrinsic relationships they hold is crucial for the ability to identify possible causes and correction of any abnormalities <ref><pubmed>21978088</pubmed></ref>

[[File:Highpowered_microscope.jpg|Left|thumb|200px|Image of a high powered microscope]]

'''Neural Crest responsibilities '''

Another Animal Study involving mice explores a new idea of [[#Glossary |'''Neural crest''']] (NC) contribution in taste development, specifically the development of papillae and taste buds. Liu HX, Komatsu Y, Mishina Y, Mistretta CM. (2012) suggest that Neural crest cells travel to the location of the tongue in early embryonic stages, gain epithelium phenotypes, multiply and then differentiate to eventually form taste papillae. The experiment involved the comparison of 2 different types of Cre line mice, which both express Cre gene in neural crest protocol, the different distribution patterns where observed in specific regions that NC is responsible for.<ref><pubmed>22659543</pubmed></ref>

[[File:Developing_tongue_histology_001.jpg|Left|thumb|200px|HIstological stain of a developing rat tongue]]

'''Augmentation of Endoderm'''

In an animal study conducted by Rothova M, Thompson H, Lickert H, Tucker AS.(2012) exploring the historically debated issue of endoderm contribution to tongue development showed promising evidence that position of taste buds are patterned by the border of ectoderm and endoderm derivative epithelium. This study was accomplished via microscopic examination of previously stained specimens. Concluding endoderm has direct influence on gustatory development <ref><pubmed>22581563</pubmed></ref>

'''Changes in Taste Cells over time'''

Research by
Ozdener H, Spielman AI, Rawson NE.(2012) developing a culture which allows taste cells to survive for up to 12 months, empowers researchers to study the processes of proliferation, differentiation and function. This experiment will provide a precedent for future study of taste cells, as these cells are able to operate and grow normally. <ref><pubmed>22643728</pubmed></ref>

'''Shh key component of taste bud proginators'''

A [[#Glossary |'''tamoxifen''']] treatment which suppresses Sonic hedgehog (Shh) secretion in mice proving to reduce the number of cells visible within papillae, in contrast mice not treated with tamoxifen showed a mark increase of cells within papillae, these cells are assumed to become taste cells in later development.
Specific mice were bred to trace the destination of taste placode cells, the study concluded that Shh expressing placodes are taste bud proginators which in turn become taste cells within taste buds although do not have any precursors relationship with papillae. The results were obtain by examination of mice embryos using Bright-field or multichannel fluorescent images through the use of an "Axiocam CCD camera and Axioplan fluorescence microscope with Axiovision software" a study by Harlow, Yang, Williams, Barlow (2011)<ref><pubmed>PMC2674259</pubmed></ref>

'''WNT family exhibit various roles''' [[File:Abnormal of tongue.jpg|thumb|200px|Image shows an example of tongue abnormalities, this is called "double tongue" each side has independent movement!]]

The WNT gene family has a function of signal2''work antagonistically through receptor tyrosine kinase (RTK)signalling.

However, the deletion of ''Spry2''led to the increase of CVPs it should be noted that they found that a significant decrease in number of fungiform papillae. In contrast, the absence of ''Fgf10'', while leading to the absence of CVPs lead to an increase in number and size of fungiform papillae. Therefore these genes have different effects on the anterior and posterior developing tongue and taste buds.ly proteins for various reason such as development, In 2010 Liu, Staubach Grosse, Walton, Saims, Gumucio, Mistretta explored recent findings on the role of WNT's in tongue and papillae development, Concluding that WNT/β-catenin is essential for fungiform papillae differing to WNT5a which proved to be principle in tongue development. Intrinsic chemical mediators were considered by manipulating a tissue culture and then thoroughly examined by scanning photomicrograph. <ref><pubmed>PMC2768563</pubmed></ref>

[http://www.surgicalneurologyint.com/article.asp?issn=2152-7806;year=2012;volume=3;issue=1;spage=23;epage=23;aulast=Manjila]

==Glossary==

* '''Circumvallate papillae''' -

* '''Ectoderm'''- outer germ layer of embryo

* '''Endoderm''' - inner germ layer of embryo

* '''Epithelium''' - basic animal tissue that is composed of tightly packed cells, usually covering the outer portion of organs

* '''Exocystosis''' - movement of contents out of cell

* '''Filiform papillae''' -

* '''Foliate papillae''' -

* '''Fungiform papillae''' -

* '''Ganglia''' - the accumulation of a nerve cell body

* '''Growth factor''' - a substance that stimulates the growth of cells

* '''Gustatory''' - anything that relates to the taste sense

* '''Hydrolysis''' - breakdown of a chemical when it reacts with water

* '''Mesoderm''' - middle germ layer of embryo

* '''Mesenchyme''' - multipotential cells

* '''Neural crest''' - a part of the ectoderm found on both sides of the neural tube

* '''Neuron''' - most simplistic unit of the nervous system

* '''Neurotransmitter''' - chemicals which allow the passing of signals from neuron to neuron via connecting part (synapse)

* '''Papillae''' - small rough surface projection

* '''Six genes''' - a family of genes

* '''Sonic hedgehog (Shh)''' - signalling protein involved in normal development

* '''Sulcus terminalis''' - describes a physical transition point separating the anterior 2/3 of the tongue from the posterior 1/3

* '''Tamoxifen''' - hormonal altering drug

* '''Type I taste cells''' - The most abundant cells in taste buds; involved in terminating synaptic transmissions (similar to the role of glial cells in the CNS).

* '''Type II taste cells''' - Receptor cells acting as primary detectors of sweet, bitter or umami taste.

* '''Type III taste cells''' - Presynaptic cells that respond to sweet, salty, sour, bitter and umami compounds.

== References ==
<references/>

==External Links==
{{External Links}}

http://embryology.med.unsw.edu.au/embryology/index.php?title=2012_Group_Project_4

http://www.webmd.com/oral-health/picture-of-the-tongue

http://www.tutorvista.com/content/biology/biology-iv/nervous-coordination/tongue-structure.php#parts-of-tongue

http://www.cf.ac.uk/biosi/staffinfo/jacob/teaching/sensory/taste.html

--[[User:Z8600021|Mark Hill]] 12:22, 15 August 2012 (EST) Please leave the content listed below the line at the bottom of your project page.

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{{2012Projects}}

Talk:2012 Group Project 3

2012-10-02T04:47:42Z

Z3330986: /* Discussion of Contributions via Email */

{{2012GroupDiscussion}}

--[[User:Z8600021|Mark Hill]] 09:54, 18 September 2012 (EST) This is a recent review on taste. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2922655 http://jcb.rupress.org/content/190/3/285 JCB content allows reuse.

==Group evaluation==

The introduction section is very informative and I like the picture included discussing the 5 basic tastes which is interesting to read. I really enjoy your descriptions of bitter and sweet and find it interesting to read. I like the research you included in this section but I believe this needs to be referenced. Currently in the introduction you have only 1 references, so I would suggest that you find more to further validate your information (note that there are no references in the first paragraph). I like in your picture that you included a description. The cell biology section I would probably put in its own section with = = to break up the contend displayed. In this section it is clear that this has been researched however there have been no references listed at all here.

The taste map section has clearly been well researched yet poorly referenced. It would be interesting to look at if possible a progression of the understanding of the taste map. In the picture of the tongue, I would suggest that it has a better description on the enlarged image. However, some of this text is rather hard to read, such as the descriptions of the first and second order neurons. As you have included terms in there which would be foreign to most people, I would try to include either a picture to show exactly where these parts are such as the NTS which can give the reader a better understanding of what you’re saying. Note that you say things like “copious scientific conjecture surrounds…” however there is no references here! This section is well researched which is great, but I would really consider putting it into slightly easier terms to better comprehension.

In the cortical areas section, a similar approach applies: when describing locations of things such as the I/fO, you should really include a clear diagram as to where all of these are. I can see you included the section of the brain however don’t see it as too informative so a better description there would be appropriate. I would also note that you are repeating your references again, and it would be advisable that you find alternative information to include as well.

The timeline section is very informative and really stands out. I’m assuming you will be including the photos later this week. This is well written and gives a truly informative description of the embryological changes that occur. It will look much better and be better to understand once the photos have been included. Note that you have used the same references pretty well the whole time in this section. Although that paper may have a lot of information about what you are needing to talk about, I would also encourage you to research more papers in order to compliment the information you have listed.

The history of discoveries section is well set out and clear and concise. In some areas I would suggest a brief descripton of what you have written such as “PKD2L”, and also make sure you include the appropriate references as all I can see currently it numbers.

In the adult tongue and taste bud section, is this also what the tongue looks like from week 15? If not what changes occurs for it to form into what you have described as the adult tongue and what enhances these changes? This section is informative however it is really lacking references. The taste bud picture you have is quite good, but is that also what the taste bud looks like at 15 weeks?

The abnormalities section is really interesting and is rather enjoyable to read. Are they the only abnormalities that can happen to the tongue? How about environmental? Does alcohol, smoking or drugs affects its development of either the tongue or the taste buds? Additonally, your current research is very thorough and interesting. In regards to the photos you have there, I would make sure that they are set out appropriately, with the information that this is a student project.

Finally, the glossary needs to be highlighted to make it stand out and more words need to be included. Note that in your references, reference 5 can not be accessible, so make sure you fix that up. Overall, it was interesting to read and I enjoyed the display of photos that were also included!

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The overall set up of the page I think is very good. In the introduction there is a balance between pictures and text which makes it a bit easier to read. Also its easy to follow, the text itself isn’t confusing and is understandable.

There is a good overview of the different types of receptors and their function, also there is a brief section on the adult tongue which is good, however there needs to be more focus on the embryological development rather than just a simple table on that. There also needs to be some images added to that component as well to make it more understandable.

The sections on abnormalities and current research need to be organised a bit better because they are a little hard to follow, especially with the placing of the images. The glossary is simple and understandable, however there needs to be more work done on the reference list.

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The layout and balance between text and figures, tables, and diagrams is extremely well accomplished. All the information of the page is really intriguing and easy to follow on the majority.
I would suggest placing the history of discoveries immediately after the introduction so that readers may appreciate all the research that would have had to take place in order to put all the information on this page. As well, this would help in having a separation between the two tables used.

When it comes to images, make sure that everything in the image is relevant to the accompanying text and important to the reader. One image where you might fall short of this criteria, is the very first image on the page about the five basic tastes, the names of the protein structures is more distracting and confusing than enlightening and overall would not aid in informing the reader.

I believe the introduction is very important in assisting the reader in gaining an overall understanding of the page and it’s aims. Hence I believe it is important to include a more succinct introduction with such aims. In this case, the introduction to the gustatory system begins defining structures and functions which are better off used elsewhere. Instead try giving an overview of the system and maybe give the reader a reason to read on.

The images used in the abnormality section are scattered and make it hard for the reader to determine which image corresponds to which idea, I would suggest ensuring that each image is detrimental to aiding the reader’s thoughts. This was an extremely interesting section.

Current research is clear, concise and easy to follow with a pleasant arrangement of ideas, text, and images. It was interesting to read. Additionally, the references and glossary are extensive and well done. I would suggest having a link to the glossary from within the text.

Well done on your project so far, and good luck with the rest.

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The introduction seemed to go into a lot of detail. for example, the information on Type II receptors should be placed in the same section as neural pathways, not the introduction. Can you also include in your introduction, an overview of what you are going to talk about in your project? That would give your project more structure.

With the neural pathway section, can you draw or find a diagram for that section? I find it hard to understand without one. The taste map section goes into a lot of detail which I think is unnecessary because this is a development project.

Current research section is very interesting. I don't think you need to add any more content on that section - that section to me looks complete, besides a few formatting and referencing issues with the images.

Overall, I felt there wasn't enough written on the development of taste, either the receptors (taste buds) or the neural pathways. Your project seem to focus on the anatomy and physiology or function of the taste system. This is alright to keep but the focus should be on development. You do have a Time-line of taste development that summarizes the development of the Gustatory system which is great to see. I think use that as a starting point and expand on each stage in text form, below the table. In week 12 development in this time-line, you mention 'epithelial types I and II', what are they? Are they similar to skin cells?

Overall, the balance between images and text is great. The colourful images work wonders in breaking up the text. Having said that, Many of your images did not have the correct PMID referencing. These images include:
* images of taste being revoked by visualizing ATP release
* CVP of WT and DKO mouse with H & E and SEM
* histology - can you give a more relevant title for this image? We know it's histology; we can see that. What is this image about?
* Abnormal of Tongue - it should say abnormality of tongue

The history section is excellent because it spans over such a long time - 350BC to 2010. The layout of a coloured table for history is beautiful, clear and concise.

--[[User:Z3332863|Z3332863]] 16:35, 23 September 2012 (EST)

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- The introduction of taste is very descriptive and encapsulates the anatomy, physiology and cell biology. Although it is very detailed it doesn’t indicate that the project is about development.

- There is a lot of detail about the taste neural pathway and cortical areas which I’m not sure is relevant to olfactory development unless you mention how they develop as well.

- Figure 2 and 3 do not have any copyright information associated so remember to add those.

- The development section is very nicely put together and hopefully you will add images further down the line. I’ve noticed that in week 8 of development you have the same ref after each line…I’m sure you can just put it at the end of the paragraph as it is same for each line. Same goes for week 14 and 15. Also since you have 2 references for the entire section --- you might want to look at other articles as well.

- Some things that I missed in the section were patterning molecules and genes. Also any signalling mechanisms that control differentiation.

- The history section is exceptionally done with the use of tables, description and references.

- I thoroughly enjoyed your abnormality section. The images are nicely done as well. Although you have described many genes and molecules which are not specified in the normal development portion so the reader don’t understand their roles. Maybe address this in your normal development section.

- The current development section is also very nicely put together but again things like Shh and WNT should be in development section.

Overall very nicely put together and great balance of pictures and text. Although this is a development topic so the major emphasis should be on development of the organ --- Normal development is good but there is too much content in that section that can be left out.

--[[User:Z3333794|Z3333794]] 10:52, 23 September 2012 (EST)

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Abundant information, including a nice coloured in table, which is a cool idea. Unfinished though, the images to go with it would make it great. The page seems to be segmented into sections with a large amount of text, and sections with many pictures. Try for a more even distribution, if possible. Pictures seem to be relevant, with good explanations, referencing and certificates. Helpful and interesting abnormalities and current research sections

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Your introduction is quite good and gives us a brief overview of the different tastes. I also like it that you touch on the fact that it is important we recognise (via taste) food which would be dangerous to our health. In my opinion, after you mention the research (ending the sentence with …’may exist.’) you should tell the reader what you will be discussing on your page. The few lines on fatty acids does not seem to fit in, and should be part of your history section and possibly current/future research. Some specific information seems to have been researched, such as what umami codes for; however, references have not been provided. Also make sure that the image has the correct information – title, description, references, copyright, student template.

It would be more logical to put the history section next. Following this by the timeline and then go back to the cell biology, receptors and taste map etc.

The history section is good with many significant dates and clear descriptions incorporated in a table. I do see lots of numbers, which I think relate to references. I cannot find these references anywhere, so please edit this and make sure it is included in your list of references. There are also a few references listed in full in the table, so please put these down as proper references. Also, there is no good description for the year 2007 (it is mainly a reference).

The developmental timeline is expansive and very interesting! It really relates to the different developmental stages and tells us what happens over time. I hope you can include images with appropriate labels and information to this table, as it will greatly complement your text. Please do check your spelling, eg. ‘epithelium’ in week 6. Also references in this section are appropriate and are not doubled-up in the reference list. Do check reference 5 as it comes up with a cite error.

The section on cell biology and type 2 receptors is clear and easy to read. I cannot see any references though! Please be careful cause this might indicate plagiarism. The taste map is interesting and I am glad you mentioned research has indicated that the different receptors are in fact located all over the tongue – not just in particular sections. If possible, look for the original paper(s) that made this discovery.

The section on neural pathways is a little more difficult to read and I did not understand some of it. Particular terms are used in sentences which suggest little effort has been put in to explain everything in your own words. This is further indicated by the lack of references in the ‘first order neuron’ section and the majority of the ‘second order neuron’ section. I might be wrong, but then do add all your jargon to the glossary. If possible, also try to find other papers which present the same information to strengthen your points mentioned. Images for both the taste map and the cortex need referencing, copyright info, etc.

Adult tongue and taste buds. It is good you include some anatomy and physiology into your section. Do keep in mind the majority of your project should focus on embryonic development. You included the appropriate names, eg. sulcus terminalis, and I am glad to see that has also been put in the glossary. Some more terms do need to be added, eg. circumvallate. The text is good, clear and easy to read. Images are appropriate and relate to the text but need proper descriptions, citations, etc. A major let down of this section is the lack of references – please include this.

Personally, I found the abnormalities section very interesting! However, you are suddenly talking about all these genes and factors which you have not mentioned anywhere else. It might be good to provide a brief description of these in the development section or incorporate them into your developmental timeline. Images all have copyright information, but other information is missing, such as the student template and/or reference. Please check and add this.

Current research includes a lot of information. All different sections have their references which are displayed in the reference list. If you can, provide links to the website of the research groups working on current projects. Be careful not to just put your reference at the end, as you may also have to reference within the paragraph. Both pictures used will need the student template. The double tongue image will need a reference in its description too.

As mentioned before, add and edit the glossary and reference list. You should also add to the useful links (make this external links) and the image gallery, or delete these subheadings, as there is nothing there now.

Hope this helps!
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"In regards to the information presented (outcomes 1 and 9), the timeline for the development is good and written with clarity. However, I noticed the section on structure only referred to the adult state rather than focusing on the embryonic origin of each structure (ectoderm, endoderm and mesoderm). I would suggest that you elaborate on the developmental stages introduced in the timeline in order to build on the information you have already provided. This is important in regards to outcome 6 so that you can relate your research to embryology – the development of taste should be your focus. The history timeline was great to read as it was very concise and clear.

The page shows a good level of peer teaching with clear language and a good balance between images and text (outcome 4) with technical terms explained in the glossary. An improvement could be to make a link between any technical language and the glossary to avoid scrolling up and down to the page. Your Current Research section (outcome 5) was very interesting to read and showed you went beyond the scope of basic research on taste – good work!

In terms of layout (outcome 2), whilst the images are interesting and relevant to the text, some are not appropriately referenced nor described; make sure to reference appropriately and at least write one or two sentences to make the images relevant to the reader. Additionally, the introduction should not be under another subheading (Gustatory system) as it creates some confusion; I would suggest making the introduction its own heading in order to make the page flow. Similarly, the history timeline would best be placed towards the beginning of the page, under the introduction.

I noticed some areas (such as the section on Structure) were not appropriately or consistently referenced. Make sure to include a citation anytime you introduce a researched idea or information to avoid being accused of plagiarism. I noticed the history timeline had good consistent referencing; however the numbers just need to be formatted so they come under the reference list. If you click on the Tutorial: References page linked from the student page, it tells you how to do this. Hope the feedback helps and all the best for your project!"

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The introduction is very detailed but did not mention anything about the development of the taste. But I thought the mechanisms behind sweet and salty tastes are very interesting. Maybe do the same for the other 3 tastes? The image of the basic 5 tastes is a bit small, maybe upload a bigger version of the image. Also, the image is lacking some reference, copyright information and a student image template.

The type II receptor section is pretty good and descriptive but it does not really relate to the development of the taste. The taste map is a very eye-catchy image and it would be really useful if it had all the needed information such as the copyright notice. The timeline of the gustatory system is very well-presented and easy to read. I understand the project is not completed yet, therefore more images are still to be put in. Only 2 references have been used in the timeline section, maybe try to research more and use different resources. There are some citing error but it should be quite easy to fix.

Histories of discoveries section is very detailed and easy to read but the referencing needs to be fixed. The adult tongue and taste bud section is very clear and precise and contain a lot of useful information but it does not really relate to the research topic, should beware of going off-track. The hand-drawn diagram of the taste bud is impressive and easy to understand but again lacking in some referencing information such as who drew it. The abnormalities section is good and well-researched and it is interesting to know about which gene or receptors will effect the development of taste and sensation. Maybe the abnormalities section can be included into the current research section because abnormalities are repeated in the current research section below. There are detailed definitions of terms in the glossary which is good because it really helps the reader to understand more about the research topic.

Overall, the page is looking good. The main thing that needs to be fixed will be the images that are already on the page, they need the correct and essential information with them when uploaded on the page or else, they will get deleted and there will be no images on the page and the nice balance of images and text now will be gone. There seem to be a lot of anatomy and biology of the taste system but not a lot of information about their development. Although there is a timeline of development but i think more information is needed. Referencing is pretty good with only one or two minor citing error but it should be easy to fix. Structure of the page is clear and simple with headings and sub-headings being consistent, making the page easy to read and follow. Hope this helps :)

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The introduction is good, explaining the function and mechanisms behind.

The taste map text and picture are useful however lack referencing information.

The cortical areas section is very interesting and well referenced.

The table timeline is a very good way to summarise the development of taste. It is succinct and well referenced, even though one paper was referred to for most of the information.

The history table is similarly good, very succinct and straightforward, however lacks some references, and the references that were included could be improved by using the wiki referencing system.

The structure and function section is useful but doesn't add much to the text in terms of embryological development. Also make sure the images are properly referenced with the "student template" included.

The abnormalities section is very good and well researched, although maybe try and avoid referring to the articles that have been researched in the text and rather just refer to them using the wiki referencing system. The images are good as well but don't forget the "student template" here also.

The current research section is interesting and well researched, the use of succinct subheadings to summarise the paper's findings was good.

The useful links and image sections need to be added to, and the glossary section can be improved by putting the key terms in bold, but that is otherwise good.

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Initially the page seems to have a good balance between text and diagrams/photographs. However the figures included are not properly labelled once you click on the file and some of them don't appear to have any copyright information included. Some of the pictures could do with being a bit smaller as they take up a large proportion of the page. The student drawn image of the tongue is particularly impressive but does still need to have the student template included. The references seem limited in comparison to other groups perhaps suggesting a lack of depth or variety of research. There also appears to be a coding problem relating to reference number 5. The general layout and use of subheadings is great. It may be useful to link the words in the glossary to their occurrence in the text.

The introductory paragraphs are very well written. They are easy to understand and interesting and give a good overview of how taste functions. Similarly the section on taste map is well written clearly explaining the neurological factors associated with taste. However the presence of the picture in isolation is confusing as it is representing an the old method of taste association. Perhaps this would be resolved if a diagram of the newer taste map was also included. Also you say that the old taste map has been disproved by recent research but that research is not referenced. In fact it appears that very little of that section is referenced. The section on cortical areas is well done.

The timeline of developmental processes is good, the table an easy visual format and the information concise and effective. The only point of contention would be the direct quote in Wk8-9 which seems out of place in comparison to the remainder of the entries which are nicely paraphrased. The history section is similarly well done being extensive and comprehensive. That is excepting some Pub Med references which are just placed in the text rather than in the reference list at the bottom. While interesting and well written the part detailing the Adult Tongue and Taste Buds seems out of place in a embryology course.

The sections on the effect of gene expression on the formation of taste abnormalities and current research are good. However it may be useful to put the information regarding each picture as a caption rather than plain text.

It will be interesting to see what is put in the section "Image Gallery"

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The information provided is both informative and well organised. The use of tables and figures make the text easy to follow and the diagrams make the information easier to understand. When it comes to images however, they seem to be somewhat irrelevant next to some of the information in some cases. Try to move them around and make sure they accompany relevant text.

The introduction does not give the reader the overview of the topic, but rather explores structures and function which makes it difficult to order. Simplifying the introduction, and moving some of the more detailed information such as the information about the type 2 receptors to the relevant section would improve the page.

Other information that is difficult to understand is the text which involves certain genes and molecules without explaining their function or role. Explaining these aspects of the genes and molecules would make the information flow better.
The section on current research is very informative and seems to be complete. However, I did note some errors with the citation of the image used, working on the references is very important for the other images as well as not all have the copyright information.

I also noticed that many of the references are repeated numerous times. Week 8 of development for example have the same reference after a number of sentences. A variety of sources will improve the accuracy of the information rather than derive all the information from a single source.

There is a great focus on the anatomy and physiology of taste, however, it is important to remember that the focus of this project is about development, and therefore including a timeline or a table which covers this information is very important. The page seems to be very organised and the inclusion of tables and diagrams along with the extensive glossary make this page stand out. Well done.

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The page that you have created is very extensive and was well formatted in relation to the ratio of images to text on the page.
Found that the colours and use of table for the breakdown of information in relation to ‘Timeline of developmental process’ and ‘history of discoveries’ condensed the material and made it easily understandable. This made me want to keep reading.

With majority of the images that are uploaded onto the page there needs to be the correct information and referencing provided for the summary box. From where the image was sourced (ideally of reliable and scientific literature in origin), identifying that it has been uploaded for a student assignment and copyright information-permission to use uploaded image and any other information that is pertaining to the topic and why the image was used/relevant.
Further, those of you within your group that have drawn an uploaded image, have to ensure that you have stated in the summary box that it was student drawn prior to final assessment/evaluation.

The glossary is able to be expanded upon and potentially ensuring that the words that are being explained/elaborated are bolded. As a reader, I would find it easier to read and distinguish if they were bolded.
The reference list that has been developed appears to demonstrate that as a group you have are well read and researched, however, the citation errors will have to be addressed and resolved prior to final marking of the project. I really appreciated the layout (headings, summary and images) of the page.

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The introduction is well written and very informative. You should add the history timeline directly below the introduction, because where it currently is feels like it is floating. With it after the introduction it will create a flow to your page and separate the two tables.
In your development table I noted a column called images, the adding of images to show the development stage you are describing will give this section some more flair. If you are not adding images don’t forget to delete the column.

Your section on adult taste and tongue is very interesting but maybe if there is a difference, i.e. newborns tongues are more sensitive to a taste than adults, a comparison would be interesting here.

In abnormalities you mention p2x receptors, maybe you could add this to the glossary and give a brief explanation about what they are and do. This would be a good idea for any other receptor or genes/proteins mention above that you don’t want to explain in detail in the main section.
--[[User:Z3220343|Z3220343]] 21:31, 25 September 2012 (EST)

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Your introductory paragraph is sufficiently detailed. However, there is only one reference. You need to show more research by adding more references to support your text. It is good that you have added an image to support the text, but you need to write that it is a student uploaded image.
Cell biology and type 2 receptors sections don’t have any references cited at all. You need to add appropriate references.

There was an image of the tongue showing the tastes in different sections of the tongue. The image didn’t have the source referenced.

The taste map section needs more referencing and citations.

Cortical area is sufficiently detailed and has appropriate numbers of references, along with a supportive image. However, you should add more description of what the image is about.
“Timeline of Developmental Processes of the Gustatory System” looks nice so far, with appropriate citations. But you may need to add some more information, and it needs to add images to support the text.

History of discoveries section looks nice, but needs a bit more texts explaining each of the discoveries. It also needs some more references, and perhaps adding some images to support the text would make it easier to visualise the discoveries.

“Adult Tongue and Taste Buds – Structure and Function” is overall lacking in text and needs more research and references. You need to explain more of the structures and functions of the tongue. The image of the ‘drawing of the tongue’ needs a bit more description in the caption. Perhaps explain what each of the labels mean. The papillae image should say that it is a student uploaded image.

Current research section is done reasonably well so far. The reference needs appropriate formatting. Perhaps reduce the size of the image showing the double tongue; it is rather graphic and somewhat disturbing.

You do not have any useful links listed. You need to add links.

Glossary section is good so far. Perhaps add some more words, and make the text bold to make it easier to spot the different words.

Image gallery does not have images under the heading.

References section: number 5 needs to be fixed.

There are not external links listed under the heading, you need to add external links with appropriate formatting.

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Group 3- Taste

Overall this is an excellent project. Well written, great informative photos, good use of tables, and comprehensive information that's well explained.

A few of the photos don't have the appropriate copyright information and some sections of text haven't been referenced, but in general this ticks all of the boxes

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Taste

The introduction is very detailed, with descriptions of the varies components of taste. Although informative, there needs to be more about the development of the different aspects of taste. I feel that the type 2 receptor part doesn't belong here as this section is here to introduce the topic (maybe put it in a separate heading or in the neural pathway section?). There also needs to be a diagram if you are to include this as if is hard to follow. The balance between text and images is good, though some of the images are not labelled or properly referenced. Histories of discoveries section is very detailed and the table was very easy to read. The section the development of the taste is very informative and shows a of effort is placed into the of research of the topic (as it is often hard when the topic is not well understood). The section on the Structure and Function of the adult tongue gives the anatomy of the tongue, and should come before the part on neural pathways. The current research provided descriptions of the research and their goal and is done well.

==Questions for group==
--[[User:Z3330986|Z3330986]] 14:29, 18 September 2012 (EST)--[[User:Z3330986|Z3330986]] 14:29, 18 September 2012 (EST)
Hey guys,

Did I see someone write about or have articles about Sprouty (''spry'') genes?

I can't find it, but I'm sure I saw it. Let me know :)

--[[User:Z3332337|Z3332337]] 11:10, 18 September 2012 (EST)

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Also, I've just been going over the main page and I wonder if a picture of the overall tongue, not only sections or histological drawings (which were really good btw) would be good to point out the anatomical features?? Like the sulcus terminalis which was pointed out.
I'd be happy to draw it. This would be for the Basic structure section.

Let me know ASAP so I can do it tonight :)

--[[User:Z3332337|Z3332337]] 11:30, 18 September 2012 (EST)

--

Yep, i think that would be a good idea. Go for it :)

--[[User:Z3330986|Z3330986]] 14:29, 18 September 2012 (EST)

Roger that (y). I'll have it done by around 10'ish tonight to be realistic.

--[[User:Z3332337|Z3332337]] 17:10, 18 September 2012 (EST)

--

Guys!!! I'm following image upload instructions to the letter and it keeps giving me database error. :( I need to upload figures 1 and 6 from this article. Let me know, k?

--[[User:Z3332337|Z3332337]] 17:58, 18 September 2012 (EST)

--
I had the same problem during the Lab assignments so i used a different image instead. I'm not sure if its related to the image itself? Maybe just email mark?

Maybe everyone could add some words from their relevant sections and hopefully we can come up with a pretty comprehensive glossary
--[[User:Z3330986|Z3330986]] 20:40, 18 September 2012 (EST)

== Discussion of Contributions via Email ==

I agree with that perhaps we have not included as much actual 'embryological' information as we should. Since neurons/the brain are important in how we perceive taste, i was thinking i would talk about the development of neurons. Let me know what you think, am i going off track?
----
Hey guys,
I know its getting late but I'm quite worried that we missed the central theme of 'embryonic development' and focused too much on adult structure and function of taste...

Please look at this article and see if there is anything relevant to your section that you can add -
[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1995452/ | Factors that regulate embryonic gustatory development]

--[[User:Z3289738|Z3289738]] 22:22, 1 October 2012 (EST)

--

Hey,
It would be nice to have pictures but they're all SEM and TEM images so they're difficult to recreate by hand. What I did instead was indicated to the reader which figure to refer to. Have a look at my section, if you think you can draw a few then that would be great!

--[[User:Z3289738|Z3289738]] 20:17, 1 October 2012 (EST)

--

Hey guys,
I changed the order of the content on our page coz I thought it would make more sense for this topic to have the embryology stuff first and then move on to details of the adult features. Let me know what you think!

Also if you can each send me a brief sentence outlining each of your sections I'll put together an intro.

Thanks,
--[[User:Z3289738|Z3289738]] 09:14, 1 October 2012 (EST)

--

Jared: hi guys,

just confirming our meeting tome tomorrow after the first lecture [after mid sem break]

Thanks :-0.

Nat:
Yup, meet outside the lecture room?

--[[User:Z3332337|Z3332337]] 11:07, 11 September 2012 (EST)

--

Hey Guys,

Jared :
becuase we are on holidays as of now, make sure we are communicating about any contributions and copy and past any email discusions onto this page.

--

Hey guys,
So here's our plan for the next few weeks. If you want you can start writing up a particular section before next week!

* Wed 5/09: Have heading finalized; divide work.
* Wed 12/09: Sections finished. Discuss in class of any areas of improvement.
* Wed 19/09: Peer Assessment!

Have a good break :)

--[[User:Z3289738|Z3289738]] 11:58, 29 August 2012 (EST)

--

Hey guys,
I thought of a few headings, please let me know if you have anything to add or change!

* Intro
* History of discoveries
* Gustatory system - this is really important!!
* Tongue and taste buds - structure and function
* Taste map
* Weekly development
* Abnormalities
* Current Research
* Future research

Not including the intro we can each choose 2 areas. I'll get started on History of discoveries and Weekly development.

If you're having problems with your section, or feel that it is irrelevant, or find something else along the way just email the group and we can make changes!

Have a great week :)

Nat

--[[User:Z3289738|Z3289738]] 10:58, 5 September 2012 (EST)

--

That sounds good, maybe we should try and meet before next wednesday to make final changes?

--

Sure, how about somewhere between the two Embryology lectures (12-3pm) on Tuesday?

Which sections do you want to do? I just put them up on our wiki page.

Nat --[[User:Z3289738|Z3289738]] 11:35, 5 September 2012 (EST)

--

well i have been already doing current research and structure + development, but im happy to do more work :) and yes perhaps straight after our fist lecture 11-12pm?

--

Jordan --[[User:Z3330986|Z3330986]] 11:50, 5 September 2012 (EST)

Hi everyone i'll be happy to "Gustatory system" and "taste map." I think it would make it a bit easier as i have covered the neural pathways of taste in some detail in Neuroanatomy.

--

Okay awesome guys

So the division of work so far is:
* Introduction to the Gustatory System - '''Jordan'''
* Timeline of Developmental Processes of the Gustatory System - '''Nat'''
* History of Discoveries - '''Nat'''
* Adult Tongue and Taste Buds – Structure and Function - '''Jared'''
* Taste Map - '''Jordan'''
* Abnormalities - '''Liz?'''
* Current Research - '''Jared'''
* Future Research - '''Liz?'''

Liz are you happy with those sections?

And Jared be careful with the 'Taste Maps' section, I just read that it may be a misconception! If thats the case then maybe just how the brain interprets the 5 different types of taste.

Nat
--[[User:Z3289738|Z3289738]] 11:56, 5 September 2012 (EST)

Hi guys,
Yes I'm happy with these sections and am on it.

Liz
--[[User:Z3332337|Z3332337]] 13:46, 6 September 2012 (EST)

--
Hi,

Can someone help me with image uploading?

The website say okay to use for commercial etc...

this is the link, is that enough information to get around copyright ????
http://embryology.med.unsw.edu.au/embryology/index.php?title=File:Structure_of_Tongue.gif

Thank you, Jared

hi guys,

just confirming our meeting tome tomorrow after the first lecture.

Thanks :-0.

== Useful articles ==

Hi there,

I'm going to links to the articles I find here so you guys can see them and I don't lose them.

===Future Research===

1) A Test for Measuring Gustatory Function
[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2823587/?tool=pmcentrez]

This is pretty good for future methods of detecting defects in taste, but requires communication about reception of the tastant. Could be used when the children grow up. Great for adults.

2) The gustatory cortex and multisensory integration
[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2726647/?tool=pmcentrez]

3) REWIRING THE GUSTATORY SYSTEM: SPECIFICITY BETWEEN NERVE AND TASTE BUD FIELD IS CRITICAL FOR NORMAL SALT DISCRIMINATION
[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2812680/?tool=pmcentrez]
(Not sure where I would put this, I'm going to put it in future research]

===Abnormalities===

1) Gustatory Imagery Reveals Functional Connectivity from the Prefrontal to Insular Cortices Traced with Magnetoencephalography
[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3132751/?tool=pmcentrez]

This article essentially highlights that taste imagery is a learned response in the Insular Cortices (IC), imaged by fMRI and PET scans, and that disruption in this learning process changes the way we perceive taste. Again, I don't know how relevant this would be in the developing embryo unless there would be damage in the pre-frontal IC.

Any ideas guys??

2) Defects in the Peripheral Taste Structure and Function in the MRL/lpr Mouse Model of Autoimmune Disease
[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3334929/?tool=pmcentrez]

3) Knocking out P2X receptors reduces transmitter secretion in taste buds
[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3188419/?tool=pmcentrez]
<pubmed>21940456</pubmed>

This was a GREAT article. Basically spoke about how using double knockout (DKO) mice for taste receptors P2X2 and P2X3 were knocked out and how it didn't release the neurotransmitter ATP when a tastant was administered, whereas the WT (wild type) mice did release ATP.

--

4) Taste Function in Mice with a Targeted Mutation of the Pkd1l3 Gene
[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2924428/?tool=pmcentrez]

<pubmed>20605874</pubmed>

5) FGF Signaling Regulates the Number of Posterior Taste Papillae by Controlling Progenitor Field Size
[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3107195/?tool=pmcentrez]

<pubmed>21655085</pubmed>

6) Taste receptor cells arise from local epithelium, not neurogenic ectoderm.
[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2924428/?tool=pmcentrez]

<pubmed>7892199</pubmed>

7) Downregulation of Dlx5 and Dlx6 expression by Hand2 is essential for initiation of tongue morphogenesis
[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3091495/?tool=pmcentrez]

--[[User:Z3332337|Z3332337]] 15:30, 16 September 2012 (EST)

===Other??===

1) Olfactory and Gustatory Sensory Changes to Tobacco Smoke in Pregnant Smokers
[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3375030/?tool=pmcentrez]

This article is unrequired for this specific project (I realised this AFTER i read most of it) because it talks about how pregnancy affects the 'want' to smoke. So it's more behavioral rather than research into developmental problems that smoking may cause.

2) CODING IN THE MAMMALIAN GUSTATORY SYSTEM
[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2902637/?tool=pmcentrez]

Liz
--[[User:Z3332337|Z3332337]] 14:09, 6 September 2012 (EST)

----

Hi guys, just putting a subheading of interesting articles found:

'''1.''' <pubmed>21978088</pubmed>

'''2.''' [http://embryology.med.unsw.edu.au/notes/tongue.htm#17108952 UNSW Embryology Development of Taste]

This website provides a really great overview of taste developmental timing & overview, tastebuds, receptors, pathways, genes and provides great references for further research - and its a UNSW site!

'''3.''' [http://www.sciencedaily.com/releases/2006/12/061205214617.htm Researchers Discover Initial Steps In Development Of Taste]

A Science News story that looks at the role of Wnt pathway in the development of taste. "In the present study, the researchers found that in mice in which the actions of Wnt proteins were blocked, taste papilla buds completely failed to develop. Conversely, in mice in which Wnt signaling was over activated, their tongues were covered with many and large papillae and taste buds." It also briefly discusses neural pathways of taste and abnormalities.

'''4.''' Purves D, Augustine GJ, Fitzpatrick D, et al., editors. Neuroscience. 2nd edition. Sunderland (MA): Sinauer Associates; 2001. '''Taste Receptors and the Transduction of Taste Signals'''. Available from: http://www.ncbi.nlm.nih.gov/books/NBK11148/

This book chapter covers a variety of transduction mechanisms for taste cells. It is quite detailed, however has some great diagrams to explain the content. The concluding paragraph provides a good summary: "The overall picture that emerges from these admittedly complicated details is that taste cells have a variety of transduction mechanisms. In general, individual taste cells respond to several types of chemical stimuli. Nevertheless, taste cells also exhibit gustatory selectivity. Like olfactory cells, the lower the threshold concentration for detecting a single tastant, the greater the selectivity of the relevant taste cell. Finally, taste receptor mechanisms also adapt to the ongoing presence of a stimulus, although the mechanisms are not understood. If a chemical is left on the tongue for a sufficient time, it ceases to be perceived (consider saliva, for example). Thus, to obtain the full taste of foods, one must either frequently change the types of foods placed in the mouth or wait a sufficient time between helpings, facts that have long been appreciated by restauranteurs and gourmets."

'''5.''' <pubmed>17108952</pubmed>
This article describes the receptors and cells involved in the different types of taste (sweet, sour, bitter, salty and umami).

'''6.''' <pubmed>17287575</pubmed>
This review focuses on the development of fungiform papillae in rodents.

'''7.''' <pubmed>15581865</pubmed>
This article focuses on the role of Sonic hedgehog on tongue and taste papilla development.

'''8'''
Liu HX, Komatsu Y, Mishina Y, Mistretta CM.
http://www.ncbi.nlm.nih.gov/pubmed/22659543
This is an article about neural crest contributions to taste development

--[[User:Z3289738|Z3289738]] 10:44, 22 August 2012 (EST)

----
Remember: textbooks are a good foundation, but articles are best to gain info from.

--[[User:Z3332337|Z3332337]] 11:32, 29 August 2012 (EST)

Hey, Just need somewhere to put this:
*[http://embryology.med.unsw.edu.au/embryology/index.php?title=Sensory_-_Taste_Development Sensory Taste Development; UNSW Embryology]
*[http://www.ncbi.nlm.nih.gov/pubmed/8955790 Embryonic and early fetal development of human taste buds: a transmission electron microscopical study] <ref name=PMID8955790><pubmed>8955790</pubmed></ref> - Can't access full article!
*[http://www.ncbi.nlm.nih.gov/pubmed/9455607 Scanning electron microscopical studies of developing gustatory papillae in humans.] <ref><pubmed>9455607</pubmed></ref>
*[http://www.ncbi.nlm.nih.gov/pubmed/9541477 Innervation of developing human taste buds. An immunohistochemical study] <ref><pubmed>9541477</pubmed></ref>
*[http://www.ncbi.nlm.nih.gov/pubmed/8241557 Evidence for stimulus access to taste cells and nerves during development: an electron microscopic study.] <ref><pubmed>8241557</pubmed></ref>

--[[User:Z3289738|Z3289738]] 11:24, 19 September 2012 (EST)

== Headings==
* Introduction
* History of Major Discoveries (early researchers)
* Time line of Developmental processes
- this is the major focus of the project (ie: developmental processes)

- week by week
** Tongue
** Taste
* Final Structure and Function of the Tongue
* Abnormal structure and function
^ these 2 can be minor sections.
* Technologies to detect abnormalities during pregnancy?
* Current research (recent findings)
* Glossary and Abbreviations
* References

--[[User:Z3332337|Z3332337]] 11:30, 29 August 2012 (EST)

Notes from Mark Hill:
* Origins of sensory
* Central pathway for taste
* Neural crest contributions
* Overview diagram of sensory diagram (can be hand drawn)
* Journal of Cell biology - Taste [http://jcb.rupress.org/content/190/3/285.full JCB]
* Links between taste and smell
* Tongue has muscular and sensory functions - segregate the two

==Division of Work==

Natalie - Normal function & abnormal function

Liz - tongue & taste development

Jordan - time line of discoveries

Jared - structure & function; recent findings

==Topic Choice==

Hey guys,
Unfortunately a lot of other groups seem to want to do hearing & vision as well, so I thought maybe we should choose to do '''taste'''. Let me know what you think!

I also brainstormed a few topic headings... feel free to add to it or change the order around

Headings:
* Introduction (what is the project about?)
* Time line of major discoveries / History (early researchers)
* Structure & Function
* Tongue development (brief)
* Taste development - time line and detailed
* Normal function
* Abnormal function
* Current research (recent findings)
* Glossary and Abbreviations
* References

--[[User:Z3289738|Z3289738]] 11:42, 15 August 2012 (EST)

----

==Lets do: Sensory - Hearing==

From a bit of research this afternoon, I couldn't find much on skin development in terms of "sense organ"/"sense development". I suggest if we do Sensory we do hearing as there was alot of information (inner, middle, outer). And also there are specific screening procedures involved during pregancy.

Couple of link below with basic surface information that we could use as a starting point.

[http://cwx.prenhall.com/bookbind/pubbooks/martini10/chapter18/custom3/deluxe-content.html]

[http://www.spuc.org.uk/education/abortion/human-development]

----

Hi guys

Organ = liver

Sensory = vision / skin / hearing

--[[User:Z3289738|Z3289738]] 12:02, 8 August 2012 (EST)

really usefull website including information on phisiology etc
[http://www.cf.ac.uk/biosi/staffinfo/jacob/teaching/sensory/taste.html]

== Stucture & Function ==

'''Structure/ Parts'''
general including tissue type muslces + mucosa etc

- anterior 2/3 and posterior 1/3 (sculus terminulis)- we are manily concerned with 2/3 of tounge as it responsible for papillae + soft palate and epiglottis containing
- papillae, contain chemo-recpetors

'''Function'''
- direct vs indriect
- parts of tounge detecting differnt tastes/ flavours

'''Pathway'''
chmeorecpetors (translation/ transduction)
process of chemical to elecectrical

User:Z3330986

2012-09-26T00:10:06Z

Z3330986: /* Lab Attendance */

==Lab Attendance==
Lab 1
--[[User:Z3330986|Z3330986]] 11:49, 25 July 2012 (EST)

Lab 2
--[[User:Z3330986|Z3330986]] 10:25, 1 August 2012 (EST)

Lab 3
--[[User:Z3330986|Z3330986]] 10:33, 8 August 2012 (EST)

Lab 4
--[[User:Z3330986|Z3330986]] 10:21, 15 August 2012 (EST)

Lab 5
--[[User:Z3330986|Z3330986]] 10:27, 22 August 2012 (EST)

Lab 6
--[[User:Z3330986|Z3330986]] 11:55, 29 August 2012 (EST)

Lab 7
--[[User:Z3330986|Z3330986]] 10:54, 12 September 2012 (EST)

Lab 8
--[[User:Z3330986|Z3330986]] 10:31, 19 September 2012 (EST)

Lab 9
--[[User:Z3330986|Z3330986]] 10:10, 26 September 2012 (EST)

==Individual Assessment==
===Lab 1===

1) As with many medical terms, ''in vitro'' is derived from Latin, translating to "in glass." It is so named, as early experiments involving tissue cultures outside of the specimen (as opposed to ''in vivo'', inside the body) were undertaken in glass containers. In Vitro Fertilization was developed by Robert G. Edwards. He was awarded the Nobel prize in 2010 in the field of medicine and physiology for his work. A link to the Nobel prize web page can be found here:[[http://www.nobelprize.org]]

2) '''Sperm counts and sperm sex ratio in male infertility patients'''[[http://www.ncbi.nlm.nih.gov.wwwproxy0.library.unsw.edu.au/pubmed/22842703]]

In this study, the sex chromosomes and sperm count of infertile men were analysed in order to determine whether infertility plays a role in the determination offspring gender. Infertility is a fairly arbitrary categorization though for the purposes for this experiment, it was taken to mean couples who had greater than or equal to two recurrent pregnancy losses or two failed IVF treatments. The subsequent results found that in men with a low sperm concentration, semen volume and total motile sperm count, there was a significantly lower proprortion of the Y-bearing sperm. Thus there is a direct link between spermatogenesis and sex ratio.

The precise mechanisms for a diminished Y-bearing proportion of sperm is unclear. It is suggested that perhaps societal stresses or individual wants and needs may play a role in the genetic makeup of sperm. Biologically, it is reasoned that an infertile man will produce less male heirs so as to minimise the chance that his offspring may encounter the same problems.

===Lab 2===

[[Image:Mouse oocytes in vitro.png|thumb|Mouse oocytes in vitro]]

In order for successful implantation to occur, estrogen controlled proliferation of the uterine epithelium must be attenuated by the hormone progesterone. Previously the mechanisms of attenuation were not well understood however recent study has shown the helix-loop-helix protein, Hand2, plays an integral role in
suppressing estrogen-driven growth of uterine epithelium. It does this by stopping the induction of Fibroblast growth factors (FGF) which are responsible for maintaining estrogen mediated growth of the epithelium. [1]

From a clinical perspective it may also direct research to improve treatments which target over-proliferative disorders such as endometriosis and endometrial cancer. Particularly endometriosis, which currently resists progesterone targeted medications.

'''Reference'''

1. The Antiproliferative Action of Progesterone in Uterine Epithelium Is Mediated by Hand2
Quanxi Li, Athilakshmi Kannan, Francesco J. DeMayo, John P. Lydon, Paul S. Cooke, Hiroyuki Yamagishi, Deepak Srivastava, Milan K. Bagchi, and Indrani C. Bagchi
Science 18 February 2011: 331 (6019), 912-916. [DOI:10.1126/science.1197454]

===Lab 3===

1) Gestational age refers to the age of the foetus/embryo beginning at the first day of the mother's last menstrual cycle. In contrast the post-fertilisation age, as its name infers, begins at the time of fertilisation of the oocyte.

2) Somites mainly generate: Skeletal muscle and dermis (from the dermomyotome) as well as intervertebral discs and vertebral bodies (from the sclerotome)

'''Histology'''

*Skeletal muscle - Contains densely packed fibers called myofibrils. These are cylindrical, long and multinucleated fibres with nuclei residing peripherally. Each myofibril is composed of the proteins actin and myosin (referred to collectively as myofilaments). Skeletal muscle can be divided into either red fibres or white fibres:

::*Red fibers are named due to the presence of myoglobin, an oxygen transporting protein, analagous to haemoglobin in the blood. They contain many mitochondria and are responsible for slow twitch contractile movements.

::*White fibers are larger with less myoglobin and mitochondria. These represent fast twitch fibers

*Dermis - Bilaminar structure composed of Papillary layer and Reticular layer.

::* Papillary layer - Superficial layer interdigitating with the dermis. Composed of loose connective tissue with thin type III collagen fibers. Also contains macrophages, fibroblasts and mast cells along with capillary loops which function in thermoregulation.

::* Reticular layer - Deepest layer containing intermingling thick elastic fibers and collagen fibers.

*Intervertebral disc - made up of fibrocartilage. The matrix contains cartilage cells, enclosed within lacunae which align in pairs or short rows between bundles of type I collagen fibers.

===Lab 4===

There are two main types of invasive prenatal diagnostic techniques

* Amniocentesis - Amniotic fluid is taken and analysed between 14th and 18th week of pregnancy. It is used primarily to test for chromosomal defects such as Down Syndrome or fetal infections. It may be used to test for maternal hypertension (''preeclampsia'') by looking for protein biomarkers.

* Chorionic villi sampling - Cells from the chorionic villus are taken between 10th and 12th week gestational age. It is used to test for chromosomal abnormalities such as Down syndrome or cystic fibrosis.

2) '''Systemic administration of a novel human umbilical cord mesenchymal stem cells population accelerates the resolution of acute liver injury'''

Traditionally when liver hepatocytes are damaged during end-stage liver disease, the only option has been transplantation. New research conducted by Burra et al (2011) however has focused upon using human umbilical cord mesenchymal stem cells (UCMSCs) as a form of regenerative treatment. In this study, UCMSCs were induced to form hepatic cell types through the use of growth factors ''in vitro'', whilst ECM components derived from surgical specimens were used as a basis of support for these cells. These cells were then transplanted into carbon tetrachloride infected mouse livers which had undergone more than 40% necrosis of its total parenchymal tissue.

When UCMSCs were recruited within liver tissue, it was found that inflammation had been reduced through the regulation of pro-inflammatory cytokines and reduction of infiltrate. Furthermore there was a higher proportion of Kupffer cells (liver macrophages) identified through histological analysis compared to untreated liver tissue. This finding lends weight to the idea that UCMSCs accelerate liver cell recovery by attenuating the inflammation process.

Another therapeutic advantage of UCMSCs was the increase of catalase activity. The amount of catalase enzyme present in UCMSC treated liver tissue was markedly increased around Day 5, resulting in enhanced elimination of reactive oxygen species (ROS) which would otherwise cause oxidative damage to hepatocytes.

===Lab 7===
1a) A satellite cell, also referred to as a muscle stem cell, is a quiescent cell which functions to repair and or form new muscle fibres.

b) Activation of satellite cells occurs primarily during muscle injury. When a muscle fibre is damaged through physical injury, the satellite cells become mytotically active and fuse with the existing muscle fibres to repair the damaged tissue. Similarly in chronic diseases such as Duchenne’s muscular dystrophy, satellite cells are activated and differentiate into new myotubes in order to replace dying muscle fibres.

2) Damage to the motor nerve, classified as a motor neuron lesion, manifests in flaccid paralysis in the affected individual. This is a result of the loss of electrical signalling from the motor nuclei of the spinal cord to the muscle spindle. Consequently the individual presents with reduced muscle tone (hypotonia) and muscle wasting (atrophy). On a cellular level, muscle fibre size decreases whilst there is a fibre type shift from type I to type II fibres. This represents a down regulation of the slow myosin heavy chain (MHC) isoform and up regulation of fast MHC isoforms. [1]

'''References'''

1. Scelsi, R (2001). Skeletal Muscle Pathology after Spinal Cord Injury: Our 20 YearExperience and Results on Skeletal Muscle Changes in Paraplegics,Related to Functional Rehabilitation. Basic Appl Myol 11 (2): 75-85,

==Peer assessment==

===Vision===

Use of historic images was good. This is a main point of difference between this project and the rest. They are however not very well integrated into the project page, they feel as if they have simply been pasted there for the sake of inclusion. Perhaps an explanation of their significance could be included as well as how these drawings have lead to more refined understandings of specific structures. The Research History section is also quite interesting although it is very brief and could be improved if it were presented in a more visually appealing manner such as in a colour table.

The development structure and function section is excellent. The text is easy to follow and the student drawn images demonstrate a clear understanding of the processes as well as giving the reader the opportunity to better visualise the different stages of development. Another image which could be included would perhaps be a histological picture (as opposed to a diagram) of the different cell layers of the retina ie. The photoreceptor layer, inner nuclear layer etc.
The current research section needs further refinement. I see no reason to simply list some current research articles except for point of reference. What needs to be done is explain how current research has changed or challenged traditional views/concepts. A brief summary of each article listed in this section is also warranted.

All images and relevant ideas appear to be appropriately cited and referenced. Image formatting on the whole is quite good although I think those included in the introduction need to be altered as they skew the text, making the section look awkward and a bit difficult to read.

===Somatosensory===

The introduction is ok, there is an imbalance between text and pictures. Particularly there is a sentence which reads “The following picture shows the general organization of the somatosensory system” however there is no picture. Also in terms of sentence structure, there are four sentences in a row which begin with “the somatosensory system...” or “the system...” Try to alternate how different ideas are expressed as at the moment the paragraph reads as a disjunct of ideas.

As a whole the page’s visual appeal needs ameliorating. There is far too much text and only two pictures, one of which is very large and appears to be compensating for a lack of smaller relevant diagrams within the body of each section. Having said this, the neural development section was very well done. It was detailed without being verbose and showed it was well researched. The hand drawn diagram is excellent. The cell biology part was also very well written and well structured however again, it simply need some visuals to aid in some descriptions of molecular processes.
There appears not to be a continuous referencing style on the page. The introduction has in-text referencing whilst the rest of the page contains endnotes. A minor problem which could be fixed easily, though quite important nonetheless.

===Olfaction===

The project page was exceptional, there is a fine combination of text and images and the images are well integrated with the presented information. I particularly like the inclusion of a hand drawn histological section embedded within the table of historical findings. Perhaps this could also be done in the next table about the developmental timeline. As it stands, this table, while detailed in its wording may be difficult to understand as there are no diagrams to show the differentiation in visual terms, from week to week.

The clinical features, anatomy, and pathohophysiology were excellent. There is not much more to say. All of the diagrams were properly cited with correct copyright information. The CT scan was also interesting to look at.

One aspect that hasn’t been touched on is future research. The current research section was very detailed and explained the significance of each new finding however as is the nature of research, there are always gaps left in our understanding or further questions that need to be resolved as a result of new information. A brief section on this would give the project more depth as it would show a level of critique rather than simply the presentation of fact.

===Abnormal vision===

From the outset the page presents as well structured, particularly the introduction which provides the reader with a clear understanding of the purpose and content of the page. The following content is detailed and well researched with equal emphasis place upon each section. It appears that the page was contributed to equally by each member.

The image comparing the fundus between albinism and a normal eye is too small. The formatting is easily fixed by including the pixel size in the image insert directory. To find out how to do this refer to the wiki reference card we were given, or online.
One minor structuring problem comes from the “ocular manifestations” sections. When it says “Major ocular disorders can be split into two separate sections based on the way in which they originated,” please list the two separate classifications immediately in bullet form. i.e.
*Genetic
*Environmental

By the time the section about the environmental origins arises, I forgot what it was referring back to and thus I had to scroll back up to deduce it was the second part of the ocular manifestations heading. Apart from this there are no other major faults of the project. All images are cited and copyright information clearly recognisable.

===Hearing===

I liked the tone of the introduction, it was light hearted and enjoyable to read, especially the image of the dog in the beginning which I thought was great. It also instructed the reader about the content of the page, thereby having a good balance between being engaging and informative.

The development section is extremely detailed, which is good in terms of showing a breadth of research and understanding however this needs to be offset with a greater deal of visual information. The subsections detailing the middle and outer ear are in need of some images showing the pharyngeal arches and their morphological changes from week to week. It would also be nice to see either some hand drawn images or computer drawn diagrams included somewhere in the page just for some variation. Towards the end of the page in the Abnormal hearing and the technological sections it tends to become very text heavy and need some image content. For example a photo of a cochlear implant would be useful.

There is some variation in the referencing style in Technology section with references appearing at the end of the section. It would be better to incorporate these references into the text as endnotes as they appear in the other sections of the project. Furthermore some of the tables are incomplete and require the addition of images. The image column in the structural malformations of the ear is empty. I’m not sure if there was a formatting problem or otherwise, though this need to be rectified.

Overall the page is very well written with an appropriate style aimed at students of the same level or higher. The glossary is extensive as is the reference list, showing an obvious depth of research.

Talk:2012 Group Project 6

2012-09-26T00:08:29Z

Z3330986: /* Student evaluations */

{{2012GroupDiscussion}}

This is a recent review on hearing. http://jcb.rupress.org/content/190/1/9.full JCB content allows reuse.

=Student evaluations=

I liked the tone of the introduction, it was light hearted and enjoyable to read, especially the image of the dog in the beginning which I thought was great. It also instructed the reader about the content of the page, thereby having a good balance between being engaging and informative.

The development section is extremely detailed, which is good in terms of showing a breadth of research and understanding however this needs to be offset with a greater deal of visual information. The subsections detailing the middle and outer ear are in need of some images showing the pharyngeal arches and their morphological changes from week to week. It would also be nice to see either some hand drawn images or computer drawn diagrams included somewhere in the page just for some variation. Towards the end of the page in the Abnormal hearing and the technological sections it tends to become very text heavy and need some image content. For example a photo of a cochlear implant would be useful.

There is some variation in the referencing style in Technology section with references appearing at the end of the section. It would be better to incorporate these references into the text as endnotes as they appear in the other sections of the project. Furthermore some of the tables are incomplete and require the addition of images. The image column in the structural malformations of the ear is empty. I’m not sure if there was a formatting problem or otherwise, though this need to be rectified.

Overall the page is very well written with an appropriate style aimed at students of the same level or higher. The glossary is extensive as is the reference list, showing an obvious depth of research.

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'''Please use this space to post your Group 6 student evaluation'''
Very clever start to the page. Introductory picture and statement draws reader in. Succinct but depth of information is really good. Somewhat overwhelming, but still very good. Break up in the information a little more.

The use of tables is really good and the coloured textbox was eye-catching and informative, similar to a textbook summary and great for wiki.

Distribution of abnormalities between environmental and genetic was also very good but further subheading for each syndrome would be better for quick access to desired information.

The development of the ear section is very well researched and informative but need pictures. I see that you havn’t gotten to really uploading lots of pictures yet but it’s really quite essential for you to do this esp. for this section as it’s the main focus. A few had drawn ones would be sufficient.

The extensive references are also impressinve.

Summary: break up sections more and more hand drawn images.

Good luck with the rest ☺

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This whole page I think is done really well. There is a balance between texts and images, it goes through the developmental process in detail, all information is relevant, there is an extensive use of resources and a pretty good glossary as well.

The image right at the beginning of the dog is very smart as it draws attention to the whole page. Also the “Can you hear me” at the beginning gives the expectation that the page as a whole is going to be really good so I thought that was very effective.

More information can be added to the current research section, and also you should try referencing throughout the entire page could be done a little better.

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Really funny image of the large eared dog is a great way to capture reader attention. It’s nice to see the importance of hearing in so many aspects of our lives. Finishing the introduction with an outline of the project is very appropriate because it sets up a framework of what you are going to talk about Overall, the introduction was very well written. The language is beautiful. However, there is a typo in ‘energy produced has be converted’.

Information presented in the history table was succinct and brief. It would be good to include proper references (in text citations) for each entry. There seems to be a gap between 1898 and 1978. Have there been any discoveries in those 80 years? It just seems like a big leap to go from the first portable electric hearing aid to a cochlear implant without any advances in hearing aid technology in between those years.

Anatomy of the ear was very clear. The text related to the picture nicely. The image enables readers to see all parts of the ear in relation to each other. It would nice to put an enlarged image of the inner ear and organ of Corti. Some people might not know what a ‘utricle’ or ‘saccule’ looks like and on that image it may be too hard to see.

With the development section, it would be good to include some images related to the development of outer, middle and inner ear. For example, include an image of week 5 embryo and label where the pharyngeal arches are so people with no background in embryology can understand what parts of the embryo you are referring to. Some of terminology, such as ‘auricular enlargement’, ‘tragus’ and ‘helix’, is hard to understand. Relevant images would help.

It would be good to put in text citations after important sentences in the paragraphs of outer, inner and middle ear development. This is because a couple of paragraphs (e.g. the middle ear paragraph) had several citations at the end of the paragraph and we don’t know which sentence or fact corresponds to which citation.

In the ‘Otic placode’ section, it’s great to see the images well referenced and have the correct copyright. ‘Early expression of Pax2 and Pax8 compared’ and ‘The expression of Sox2 and Sox3 during development of the ear’ images were useful because they reflected the processes outlined in the text. Maybe simplify the signalling information on the FGFs because I found it hard to understand. Maybe give a summary of the roles of the major factors – a table, showing ‘factor...process it controls’, would be nice.

‘Recent model related to sensory fate’ image made a complex process simple – this is great to see. ‘Establishing polarity and formation of inner ear structures’ section was very well written. Maybe put this under the same section as the inner ear. I feel the 2 sections are related.

Abnormal hearing section was very detailed and extensive. It covered so many hearing abnormalities. It would be good to include available treatments for some of the diseases and give a summary table – ‘causes...disease...description of disease...prevalence...treatments’.
--[[User:Z3332863|Z3332863]] 14:34, 25 September 2012 (EST)

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"The humorous image at the beginning accompanied by the “CAN YOU HEAR ME” in the introduction was a very clever way of drawing the reader in and making your message loud and clear, with all pun intended. Great work! I like how you also clearly introduced what your page will discuss.

No issues with the history timeline – it is well set out and very clear and concise. The section of the Adult Anatomy is quite clear also, however you refer to histology in the title – perhaps include an image that shows the histology of a certain structure. In regards to the section on Development, it is very clear that a lot of work has gone into this. However, be aware that you must reference all your information to avoid being penalised or accused of plagiarism. Additionally, images would help your explanations – it is slightly word dense at the moment so perhaps arrange some of the content into dot points in order to engage your reader. The sections on the Otic Placode and Otocyst are great examples of webpage layout, with the dot points and a clear image which links to the content. I especially liked how a summary of the inner ear was included – this demonstrates an awareness of peer teaching and reiterates your key points. Excellent!

The section on abnormal hearing was a joy to read and was cleverly set out in tables – the information will be even more enhanced by the images I can see you have indicated you will add. I also liked how you divided the different congenital abnormalities into environmental and genetic. In order to enhance these sections, incorporate some dot points or a diagram showing how viruses/drugs can cross the placenta.

The “Technologies to Detect” would best be organised under subheadings – at present it is a little daunting to read in the paragraph-paragraph format which is a shame because the information is very interesting! Also, be aware of correct referencing formats which you can find on the tutorial page – your in text references should be numbers and the references should go at the end of the webpage. I liked the “Technologies to overcome the problems” – may I suggest including images or diagrams of these technologies?

It would be great to see more examples of Current Research. However, what you have presented thus far is great – you have clearly described the aims and findings of research.

Overall, good work – just make sure you are consistent with referencing and strike a balance between images and text."

------
What drew me into reading this page, was the humerous image at the beginning together with the perfect introduction that encourages people to read on. The sub-headings, headings, figures and tables make it really simple for the reader to take in all the key points of the research area. I particularly like the inclusion of technologies to detect abnormalities. However, this great balance is not met in the development section where there is too much text and not enough images or diagrams to guide the thinking. I would suggest trying to simplify the information into key points by eliminating any information that would not necessarily contribute to a sound understanding of the topic. This could possibly be achieved further by having a separation or different sub-heading for the description of the development process and the description of the cellular structure.

What stands out the most about this page, is the amount of research you have put in to the genetics and molecular processes of development and abnormalities. Whilst it is very interesting and shows the amount of time you've put into having a clear understanding, at times it seems the naming of genes and their proteins do not contribute to a sound understanding but rather adds confusion. For example, your reference to FGF and Sox are important but you have further included the different types of FGF and Sox proteins without offering much of an explanation about what distinguishes them from eachother. Generalising in these cases (to just FGF not FGF1,2,3..) would not limit the extent to which a student may learn from your information but will avoid any confusion.

Another way you could further improve the page is with the inclusion of student-drawn images or learning aids to accompany the text. This way you can avoid the inclusion of unnecessary information on borrowed images, for example, the wild-type inner ear morphology image. The referencing system is consistent and well set-out on the page and the long list of references and interesting discoveries is impressive. Overall I would just encourage condensing the information into dot points that help simplify the reader’s understanding.

Good luck!

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Good use of image, it attracts my attention straight away and it is very relaxing to look at a funny image before reading the text. Introduction is precise and to point, clearly identifying the purpose of the project and gives a general overview of what the readers will see or learn from the project. The timeline for history is good, but maybe indicate what kind of history is it? The adult anatomy and histology section is good but the heading should be "adult ear anatomy and histology"? I like it how the ear is divided into outer ear, middle ear and inner ear and then it is further divided into components that are included in these 3 different parts of the ear. This makes the structure of the ear very easy to understand and we can locate the different structure of the ear much easily. The image used in this section is very good with clearly labelled structures, the image also contained all the important information and referenced correctly but you forgot to include the student image template.

The development section is well-researched and contain a lot of information. More images should be put in to balance out the heavy text load in the section but the information provided is very in-depth and precise. The developmental process is explained in simple terms but i noticed that there is an imbalance in terms of research and information between middle ear and the other two. Maybe more research should be done on the middle ear. The summary of the inner idea was a good idea because it clearly points out the main points that readers should know, should consider do something similar for both the outer and middle ear.

The abnormal hearing section is well-researched and interesting. It is very nice to know about the association between gene mutation and its influence on hearing development. Maybe some images should be put here to balance out the text a bit. The table of genetic syndrome is very nice, maybe you can consider putting the gene mutations into table as well. The environmental section is nice and well-researched but maybe images should be put here because right now it is pretty boring just going through all the text. And there are just some weird reference under each infections but i think this can be fixed soon. Structural malformation of the ear table is nice as well, clearly showing all the important information. It will look even better when all the images are put in.

Overall, i thought the project is really good. Contained a lot of useful information and a lot of research effort has been put in, all the information are related to the research topic. The tables work really well and the structure of the page is easy to follow. Referencing is generally good but maybe get rid of some of the random citations in sections. More images should be put in to balance out the heavy text but I thought it was a very well-researched project. Hope this helps :)

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Group Assessment Criteria:
# ''The key points relating to the topic that your group was allocated are clearly described.'' The introduction clearly outlines the key points of the project and the content is well described in the text.
# ''The choice of content, headings and sub-headings, diagrams, tables, graphs show a good understanding of the topic area.'' The choice of content and headings shows a good depth of research and understanding of the topic area. The ‘Summary of the inner ear’ table was a good idea and ties in all the information nicely.
# ''Content is correctly cited and referenced.'' There are large paragraphs of texts that have no references. The images provided display the copyright notices and explanations.
# ''The wiki has an element of teaching at a peer level using the student’s own innovative diagrams, tables or figures and/or using interesting examples or explanations.'' The introduction is well written and catches the readers interest and attention. Most of the normal development section is easy to understand, however the abnormalities section is difficult to understand due to the scientific jargon. Some hand-drawn images and tables would be beneficial in order to reduce the large paragraphs of text.
# ''Evidence of significant research relating to basic and applied sciences that goes beyond the formal teaching activities.'' The amount of information provided is evidence of the significant research that went into this project, and the sections such as ‘Technologies to overcome the problems’ shows research that goes ‘beyond the formal teaching activities’.
# ''Relates the topics and content of the Wiki entry to learning aims of embryology.'' The topics and content are well related to the learning aims of embryology
# ''The content of the wiki should demonstrate to the reader that your group has researched adequately on this topic and covered the key areas necessary to inform your peers in their learning.'' All the content is relevant to the key areas of the development of the eye and demonstrates an extensive amount of research into the topic.

Additional points:
* The amount of text is overwhelming. You should make better use of tables, figures and diagrams to breakup/replace the text.
* Adult anatomy and histology: no reference to histology. Would be beneficial to have a brief explanation of the functions of each structure.
* Overall impression: Very well researched topic and I'm sure the use of tables, pictures and diagrams will make it more appealing to read!

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The image of the dog at the top of the page, while amusing, is not helpful nor appropriate for the academic nature of this website. The rest of the page however, is quite good. The information is extensive, very extensive. What i particularly like is that you have included a large amount of information on the actual development of the sense. It is easy with this assignment to talk at length amount the gross anatomy/physiology of the sense, without really dealing with the embryology of it.

As with most of the other projects, there are some sections that would benefit from a diagram or image. I know this is hard, especially for a paragraph dedicated to "mutation of gjb2 gene", but the large bloc of text is really quite trying for the reader. I found myself losing interest quite quickly.

Reference list is well pull together with a large body of research giving weight to your summary/ideas. Another this of note is how well explained your images are. This provides valuable information in trying to understand some of the ideas presented.

This is some discontinuity between the sections regarding how your present and list your information. This is probably just a by product of teamwork that can be ironed out easily.

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The introductory image at the top of the page is very good but the "can you hear me' bit was overkill for me - maybe consider revising that. Also the small spelling mistake at the start of the introduction (should be senses not sense) is quite off-putting and should be fixed. Otherwise a good introduction.

The history timeline is very good and serves as another good introduction to the topic. Some external links are missing here though.

For development there is a lot of information in the outer ear section but not much in the middle and inner sections - it looks imbalanced and may be improved by adding to the other sections or perhaps splitting up the sections differently. Other than this the development section is very good with a lot of well researched information. The images are also good but don't forget to add the "student template". The inclusion of the summary box is a very good idea and is a good feature of the page.

The abnormal section is also very good and well researched. The subheadings are used effectively and the tables are a good addition. Adding images in the tables as well as the text will help to break up the text and promote interest.

The technology sections are an interesting addition however could be improved by referencing using the wiki system rather than standard in-text citations.

A good start has been made in the current research section however if possible add more current topics of research.

The glossary is very good and the references are extensive however don't forget to add to the external links.

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Firstly the use of humour in this page is brilliant! Makes for an interesting and engaging read. The use of photographs and figures are particularly useful to help understand the topic but don't forget that the student template notice needs to be added to each photograph/diagram that you include. The referencing is great and extensive, perhaps though it might be an idea to see what is going on with reference number 56. The general layout of the page is really attractive too with a good balance of images and text, tables and especially the colourful Summary box. The content seems to address the course aims and requirements.

The introductory paragraph is to the point, well written and engaging. Similarly the structure and content included in the historic section is detailed and easy to read due to the table layout. The section about the development of the inner is well written but is somewhat overwhelming to look at just because of the amount of text. Maybe this could be combated by separating it into a few more paragraphs. The inclusion of genetic information in this area is great. The information under the subheading "The Otic Placode" onwards is particularly well done.

I like how the section on abnormalities is set out. However one problem with the area is the NOTE just before the table of genetic syndromes, I don't understand its purpose. Similarly the link in Goldenhar Syndrome entry appears random in comparison to the remainder of the entries.
Perhaps some more images in the abnormality section would be beneficial in breaking up the text. The paragraph discussing Rubella has two sentences in brackets at the bottom. Not sure why they are there either. If possible make "Infections" and "Drugs" into subheadings. I assume that information is still forthcoming for the section on Isotretinoin.

"Technologies to detect" is a good entry but perhaps consider changing subheading title as it is a little vague and incomplete. Also with this section there are loose references which should be included in the reference list at the bottom of the page rather than in the middle of the text. The information on hearing technology is brief but to the point. Again with the section on current research it may be an idea to include subheadings rather than bullet points, just so it is more easily accessed from the contents box at the top of the page.
Hope this helped.

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The introduction gives a good overview of the project and serves its purpose well. In addition, the technology section is another thing that stands out in this page along with the glossary and extensive referencing. These sections don't need to be worked on, but rather concentrate on expanding the page and adding a few more subheadings including headings of "current treatment" and "infection".

Information is very easy to follow due to the right choice of subheadings, tables and graphs. A few more tables and images with labels would make the information even easier to understand. Sometimes the amount of information becomes overwhelming, therefore try to break up the amount of texts by adding diagrams in between. Student hand drawn diagrams would be an excellent tool to employ as they can go well with the information provided.

The division of information between inner/middle/outer ear makes the structure easy to follow. This is a very good idea and an example as to how to break up the rest of the information which is all crammed together.
The citation and referencing seems to be correct, however, there are a number of paragraphs without any references, this is something that needs to be looked into. However, the level referencing at the end is great.

Also, there does not seem to be enough links. A few external links will benefit the page and allow readers to interact a fraction more.
Overall the page is very informative, however, altering the outlay and including a few diagrams, labeled images and external links would make the information easier to apprehend.

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Overall this is a well written page and is thoroughly researched.
While your introduction is small it is to the point. It gives an overview of hearing, its importance and outlines what your page is going to discuss.

The adult anatomy and histology part is confusing, I assume the adjacent image is related to the section and that development is a separate section. If that is so maybe the ear image should be thumb nailed or made smaller so that development looks like its own part.

Some images for development would be a nice addition to the well-researched information. While the class understands what it means others searching this page will have no point of reference as to what pharyngeal arches are for example, this is only a minor problem though.

The format of your development section is slightly confusing. Maybe by adding a line under inner and outer ear it would define it as a section on the respective area of development. I do like the summary of inner ear development at the end.

Technologies to detect, could possibly be name detection technologies/techniques has in text citations, I don’t think that these are necessary for this type of assignment.
--[[User:Z3220343|Z3220343]] 21:34, 25 September 2012 (EST)

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Group 6-Hearing

-you had me at puppy

-good intro (a few typos) and history (I like your table)

-the start of adult anatomy and histology should have an opening sentence instead of just listing information. There is no histology?

-I'm guessing the heading for development is meant to be bigger instead of it appearing to be part of "adult anatomy and histology"? This section is very comprehensive!

-your "neural domain" drawing is a good way of explaining this concept

-the summary box is a great idea, but perhaps it should be entitled "Summary of inner ear development"

-I don't understand why this is present- "NOTE: DEFINITIONS OF SYNDROMIC AND NON SYNDROMIC HEARING LOSS". You have explained what non-syndromic hearing loss is in the 1 Mutation of GJB2 gene section, but as your note says, it might be good to have a brief section with these definitions

-your genetic and structural disease tables are nice but I feel that the formatting should be the same for all of the diseases, or you should explain why you've chosen to emphasise these abnormalities

-the PDF in the Toxoplasmosis section seems to have some good info, but should be formatted like the other references

-the references in the rubella, cytomegalovirus infection, drugs and technologies to detect sections need to be formatted properly. Some info in drugs section isn't referenced at all

-technologies to detect is not a very informative heading, you need to specify what you're detecting. The syntax in this section and "technologies to overcome the problems" is poor (including the headings)

-in text hyperlinks in current research section are good for making page more interactive

-you appear to have used a lot of great resources

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Hearing review:

This group successfully energies the audience with a funny picture, along with a great introduction and an interactive writing style from the first paragraph. This page needs to address the reoccurring text to image ratio, allowing the reader more explanation complementing the hard work of explaining concepts. The highlight of this text was the abnormal hearing section which I found to be very interesting along with sound presentation of ideas. The demise of this page is the lack of information in current research and being starved of visual stimuli.
Overall a good attempt to line up embryological teaching concepts, when these easily addressable points are responded to a commendable finish will be apparent.

--[[User:Z3330795|Z3330795]] 09:55, 26 September 2012 (EST)

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Introduction needs more details. It has no references, so you need to research more and write more details with references. It would be good if you add an image of the ear with its structural components labelled, and explain the function of the structures.
The history section is too short so far. It needs more details and more references. Also, it would be good if you add images to support it.

Adult Anatomy and Histology has a good image, but you need more text details and you need to explain the structures more properly. And although ‘histology’ is mentioned in the heading, there is no explanation of the histology of the ears in the section at all. You need to reference the explanations of the ear structures.

Development section has a lot of detailed information so far, but needs more references and more images to balance the text. There is too much text but not enough images. The images that are currently there needs more description in the image details.
Genetic syndromes has a column that is labelled ‘images’ but there are no images there. You need to add images there.
Abnormal hearing section is very detailed and well done so far. However there is too much writing and no images at all. You need to add more images to balance the text to make it easier to read.

You may need some more examples in “Technologies to overcome the problems” section and you need to add more reference to the information posted so far.

Current research section needs a lot more work. Please add more article summaries and images with description from the articles to support the text.

Glossary section is good so far, but perhaps add some more words.
The reference section is good so far and has correct formatting.

There are no external links listed as of yet. Please add some useful external links.

---

=Hearing=

Normal and Abnormal

==Discussion Topics==

===Introduction===
Not what hearing is but what we are going to talk about

Image for hearing <pubmed>20624897</pubmed>
===History===

Research Contribution

==== Bartolomeo Eustachi 1514–1574 ====
Proposed that the tympanic membrane was connected to the nasopharynx was in the book ''De Auditus Organis'' in 1563. This was focusing on the the middle ear. His knowledge had allowed him to rediscover the tube found many years before and describe it correctly. This tube, the eustachian tube was named after him, by Antonio Maria Valsava and was shown in his book ''De aure humana tractatus''. <ref name="/PMC1142106"/> [http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1142106 De aure humana tractatus.]

==== Antonio Maria Valsava 1666-1723 ====
The pioneer in the anatomy of the ear, published his first book ''De aure humana tractatus'' in 1704 this was the first to show and clearly describe the ear. He had been able to describe the anatomy and physiology of the ear by dissecting over thousands of corpses. He was able to separate the ear into its divisional compartments of inner, middle and outer ear.

===Adult Anatomy and Histology===

<pubmed> 15495168 </pubmed>

<pubmed> 16015653 </pubmed>

<pubmed> 9433684 </pubmed>

===Development===

<pubmed> 6650859 </pubmed>
====Outer Ear====

Historic paper

<pubmed> 17104502 </pubmed>

<pubmed> 22296782 </pubmed>

<pubmed> 12874121 </pubmed>

====Middle Ear====

<pubmed> 18803631 </pubmed>

<pubmed> 21196256 </pubmed>

<pubmed> 14973294 </pubmed>

<pubmed> 11237469 </pubmed>

<pubmed> 16600992 </pubmed>

====Inner Ear====

(can include balance organs as well)
cochlea and semi circular canals and the physiological function - how hearing works

Some papers to start with:

<pubmed>15319325</pubmed>

<pubmed>17891709</pubmed>

<pubmed>10887092</pubmed>

<pubmed>19247974</pubmed>

===Abnormal Hearing===

Just putting my articles in here so I can refer to them at a later date - will change the referencing when I have structured my points better

- DISCUSS CONDUCTIVE AND SNESORINEURAL HEARING LOSS
- ADD PICTURES OF GENETIC TRANSFER
- ADD PICTURE OF LOCATION OF GENE GJB2

Genetic defects:

1. [http://ghr.nlm.nih.gov/gene/GJB2| GJB2 Gene] (accounting for 50% of non syndromic hearing loss)

Environmental

1. Drugs:
Hearing, Speech, Language, and Vestibular Disorders in the Fetal Alcohol Syndrome: A Literature Review. Michael W. Church and James A. Kaltenbach, Alcoholism: Clinical and experimental review. Vol. 21, No. 3, May 1997 [http://www.ncbi.nlm.nih.gov/pubmed/9161611| PMID: 9161611]

2. Infections:
Congenital Rubella Deafness: A preventable disease. C. S Peckham, J. M Martin, W. C Marshall, J. A Dudgeon, The Lancet, February 3, 1979 [http://www.ncbi.nlm.nih.gov/pubmed/84910| PMID: 84910]

[http://www.ncbi.nlm.nih.gov/books/NBK1434/ |Deafness and Hereditary Hearing Loss Overview]

Etiological diagnosis in the hearing impaired newborn: Proposal of a flow chart. De Leenheer, E.M.R. ; Janssens, S. ; Padalko, E. ; Loose, D. ; Leroy, B.P. ; Dhooge, I.J. International Journal of Pediatric Otorhinolaryngology, 2011, Vol.75(1), pp.27-32

[http://sirius.library.unsw.edu.au:9003/sfx_local?frbrVersion=3&ctx_ver=Z39.88-2004&ctx_enc=info:ofi/enc:UTF-8&ctx_tim=2012-08-26T10%3A07%3A34IST&url_ver=Z39.88-2004&url_ctx_fmt=infofi/fmt:kev:mtx:ctx&rfr_id=info:sid/primo.exlibrisgroup.com:primo3-Article-sciversesciencedirect_elsevier&rft_val_fmt=info:ofi/fmt:kev:mtx:&rft.genre=article&rft.atitle=Congenital%20cytomegalovirus%20(CMV)%20infection%20as%20a%20cause%20of%20permanent%20bilateral%20hearing%20loss:%20A%20quantitative%20assessment&rft.jtitle=Journal%20of%20Clinical%20Virology&rft.btitle=&rft.aulast=Grosse&rft.auinit=&rft.auinit1=&rft.auinitm=&rft.ausuffix=&rft.au=Grosse%2C%20Scott%20D.&rft.aucorp=&rft.date=2008&rft.volume=41&rft.issue=2&rft.part=&rft.quarter=&rft.ssn=&rft.spage=57&rft.epage=62&rft.pages=57-62&rft.artnum=&rft.issn=1386-6532&rft.eissn=&rft.isbn=&rft.sici=&rft.coden=&rft_id=info:doi/10.1016/j.jcv.2007.09.004&rft.object_id=&svc_val_fmt=info:ofi/fmt:kev:mtx:sch_svc&svc.fulltext=yes&rft_dat=%3Csciversesciencedirect_elsevier%3ES1386-6532(07)00336-8%3C/sciversesciencedirect_elsevier%3E&rft.eisbn=&rft_id=info:oai/%3E| Congenital cytomegalovirus] (CMV) infection as a cause of permanent bilateral hearing loss: A quantitative assessment. Journal of clinical virology [1386-6532] Grosse, Scott yr:2008 vol:41 iss:2 pg:57 -62

Congenital Infections. JF Bale. Neurol Clin. 2002 Nov;20(4):1039-60, vii. [http://www.ncbi.nlm.nih.gov/pubmed/12616680| PMID: 12616680]

Related to both middle and inner ear (so we can link the technologies to this)

===Technologies to detect===
Any technologies (like pre-testing) that identify any problems with hearing development

===Technologies to overcome the problems===
(hearing aids, cochlear transplants, etc)

===Current Research===

===Glossary===

===References===

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Allocated subheadings

J: adult anatomy, outer and middle ear development

M: Inner ear

P: History and Technologies

B: Abnormal Hearing

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==Our Thoughts - put new comment at the top please==

Hey all! We are starting to get some really good and useful feedback :) Hope everyone is ready to get stuck into editing from tomorrow onwards, cause the project is DUE WED 03/10/2012 - WHICH IS NEXT WEEK!! Keep this in mind. From what I read so far, the aim will be the simplify/reduce our text and include more images. Referencing needs to be fixed as well for some parts of the project.. but all in all its quite good :) M. --[[User:Z3333865|Z3333865]] 09:03, 25 September 2012 (EST)
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Hey! To everyone who is working on the history, please add this to the table! I'm about to change it now so that there is simply one table with significant dates and explanations. And it would be good if we can quickly meet up after one of the lectures tomorrow :) anyone who can't make it, please let the others know. M --[[User:Z3333865|Z3333865]] 14:31, 17 September 2012 (EST)

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Hi P,
How are you going with your research? We really need to have it complete by this weeks lab so that we can spend the next couple of weeks adjusting the information. Thanks, B --[[User:Z3292017|Z3292017]] 12:08, 17 September 2012 (EST)

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Hey M,

Yeah summary sounds like a good idea and maybe wiht some bolded words etc? Ive created 2 tables where I will briefly summarise the remaining diseases such as structural and genetic syndromes as my section will be too long and more boring than what it already is if I keep going. Yes, I think by our next lab would be a good idea. B. --[[User:Z3292017|Z3292017]] 19:22, 15 September 2012 (EST)

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Hey B and others,

My section is almost finished. I mainly have to focus on the images. I was also thinking of putting a summary box in my section, because there is just so much text! About the due date.. I think it will be good for us all to have most of the research and text done by lab 8 (19/09/12). We can then focus on the layout and images and tables, etc. What do you think? M. --[[User:Z3333865|Z3333865]] 17:57, 15 September 2012 (EST)

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Hey guys,
I have been updating all of my abnormalities and along with the references, it will all be completed by Sunday night, exempt all the photos as that will be my final research. Thought I would update you all so we can get a finish timeframe in mind!
B. --[[User:Z3292017|Z3292017]] 15:08, 15 September 2012 (EST)
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Hi P,
In regards the technologies, you should take a look at my section, because the technologies should really be perhaps how abornal hearing can be detected in the womb (such as amniocentesis for Rubella) and also the different insstruments used for hearing and why they do and don't work on certain patients. and perhaps with the history go a bit more indept/ greater explanation. such as if the first hearing aid was developed, find a picture and say what they originiall used to create noise for the patient etc. Use bulletpoints if you don't want it to seem too full on Do you guys agree?
B. --[[User:Z3292017|Z3292017]] 15:02, 15 September 2012 (EST)
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Hey P.
The history section should contain major discoveries and the person(s) of interest. I started writing things down in a table. If anyone find info they should put that in and the original document/article should be referenced if possible (not a review). Hope this helps cause we really have to put all our info together soon. M. --[[User:Z3333865|Z3333865]] 12:40, 14 September 2012 (EST)
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Hey guys, for the history, im not 100% what I supposed to write about, i know its late and i'm an idiot for asking now, but am i supposed to write like the old research papers like what they used to think? like how they thought the ear formed like from the 1800's or whatever? and how technologies also helped proved it wrong or proved that they are right? P. --[[User:Z3333431|Z3333431]] 13:13, 12 September 2012 (EST)
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DW, I had a look at the editing basics and the references are working now! :) M. --[[User:Z3333865|Z3333865]] 10:20, 3 September 2012 (EST)

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Hey ppl!

I can't seem to link my references. '9' and '10' in my inner ear section step 2 should be the same number, but I can't seem to get it to work... can anyone help?

Thanks, M. --[[User:Z3333865|Z3333865]] 09:46, 3 September 2012 (EST)

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To all,
I find it very difficult to find images which have the correct copyright statement and are not already used on this embryology website.
So if anyone finds an image which we are allowed to use, please post it up and let the others know :)

And to B. That sounds good :) Speak to you tomorrow! M. --[[User:Z3333865|Z3333865]] 13:22, 27 August 2012 (EST)

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Hi!

In regards to my abnormalities (we can all discuss further this week), I will be focussing mainly on the gene GJB2 (which accounts for 50% of non syndromic hearing) and then for acquired hearing (organisms), I will focus mainly on what is known as "TORCH" organisms (i.e., toxoplasmosis, rubella, cytomegalic virus, and herpes) and go into details in them and then as M said before, just list the other in a table.

Thanks,
B. --[[User:Z3292017|Z3292017]] 17:45, 26 August 2012 (EST)

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Hey!

In regards to the hearing abnormalities, yes I would do the most common ones. It will be way too much otherwise!
Just name the other abnormalities for now - depending on how long your section is we will include them or leave out.
At the end of your section we can also put a table down with a summary of the common ones you explained in detail before :)

M. --[[User:Z3333865|Z3333865]] 13:07, 26 August 2012 (EST)

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Hey guys,

Sorry I haven't been communicating via the discussion page, I've been sick in bed with a virus for the past week and half! Anyway, as I am focussing on the hearing abnormalities, I just wanted to clarify some things with you all. Firstly, there are A LOT of genetic disorder which contribute to hearing loss so I was thinking I would group them and would write in depth into the most common ones and then a brief description or just name the others.
I'm currently compiling some research papers, so I will most likely get to writing some points on this page tomorrow.

Let me know if you have any suggestiosn etc and if I find any other articles in my research I will send them through!
--[[User:Z3292017|Z3292017]] 18:44, 25 August 2012 (EST)

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Hey all!

For this week, please find some good papers relating to your section - both primary and secondary - and start reading them.
It will take some time to get all the info together and to also make it look good with pictures etc.
So the sooner we start the easier it will be in the long-run!!

--[[User:Z3333865|Z3333865]] 21:00, 18 August 2012 (EST)

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Hey everyone!

I guess if we end up doing the sensory topic and focus on the ear we can come up with some headings that we might want to use in our project.

This is the [[Sensory_-_Hearing_and_Balance_Development| link to our lecture on the ear]]

I guess one way of doing this would be to divide it into inner, middle and outer ear and talk about the development of each. I guess we could include the progressive development over the weeks including cellular, molecular and morphological changes. We can also describe the developed ear, any genetic mutations or incorrect signal pathway that cause any defects. Then one part of it can be current research and any past research or noble prizes.

Cheers!

--[[User:Z3333794|Z3333794]] 11:31, 9 August 2012 (EST)

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Hey all!

So we have to decide between normal development or abnormal development.
Normal development can have headings as mentioned above, apart from the genetic mutations and defects.
When focussing on abnormal development of the ear we can look at those mutations and defects. We can also look at technology such as hearing aids and the cochlear implant.

Please put down your preference!
I really dont care.. but I think that if we have to discuss development it will be easiest to look at normal development.

--[[User:Z3333865|Z3333865]] 13:06, 14 August 2012 (EST)

Talk:2012 Group Project 5

2012-09-26T00:06:33Z

Z3330986: /* Group evaluation */

{{2012GroupDiscussion}}

==Group evaluation==

From the outset the page presents as well structured, particularly the introduction which provides the reader with a clear understanding of the purpose and content of the page. The following content is detailed and well researched with equal emphasis place upon each section. It appears that the page was contributed to equally by each member.

The image comparing the fundus between albinism and a normal eye is too small. The formatting is easily fixed by including the pixel size in the image insert directory. To find out how to do this refer to the wiki reference card we were given, or online. One minor structuring problem comes from the “ocular manifestations” sections. When it says “Major ocular disorders can be split into two separate sections based on the way in which they originated,” please list the two separate classifications immediately in bullet form. i.e.
*Genetic
*Environmental

By the time the section about the environmental origins arises, I forgot what it was referring back to and thus I had to scroll back up to deduce it was the second part of the ocular manifestations heading. Apart from this there are no other major faults of the project. All images are cited and copyright information clearly recognisable.

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Your introduction is rather succinct which I like but I would encourage you to put references in this section. I would also suggest that you split it into 2 paragraphs to make it easier to read. Perhaps maybe you could put a photo of a normal eye in this section to show what it should look like, and then throughout the paper as you discuss the abnormal developments, you it could give the reader a better understanding as to how exactly this has altered the eye using the comparison.

The Normal eye development section is good as it provides a way for the reader to compare the differences in progression when referring to the different abnormalities listed below. However I would possibly suggest this to be put in a table, with perhaps a sentence at the top saying something along the lines of in order to fully comprehend abnormal development, an understanding of normal eye development is important - that way the reader can understand why you put this section in. I would also suggest a picture here.

The abnormal lens development section is clearly very well researched with a wide range of references. I like how you have separated the development in to the different sections of the eye as this can give a more thorough insight into these abnormalities. I think this section has been well written, and the only suggestion I would have would be in regards to the photo presented. Perhaps include some arrows to point at the sections you’re talking about and discuss what the nuclear area of the lens is?

The anormal corneal development and the abnormal retinal development are very descriptive and well referenced. I would perhaps look at moving the photo in the corneal development up a bit more and again I would provide more of a description of what is shown. If possible, I would try and make the abnormal retinal photo bigger.

Ocular manifestations is a bit confusing as im not sure if it’s a new heaing all together of if it is supposed to be part of the broad category of abnormalities. Your genetic section is well researched, I would just be careful in referencing the same paper too many times (25 is listed 5 times in this section) and perhaps try and find some other papers which compliment this research? I would probably put your reseach timeline at the bottome and include all of the treatment and clinical manifestation flowing on from each other. Note that in the research timeline, this is purely from one source, reference 26, and I would advise that you find alternative sources as well – im sure there would be individual research papers for each new date??

The anophthalmia section im assuming is still part of genetic abnormalities and I would recommend starting with the genes which are affected – to create a flow on effect. Other than that it is well references and easy to read. In regards to your photo I would have a description of what the photo is about in the enlarged view to assist with the readers comprehension. Also, at what point can these abnormalities be detected in the womb – either from an ultrasound or from sampling of the genes or something - and does this have an affect on whether the mother keeps the child or not? I think the environmental causes of abnormalities are good and I would suggest that you add photos here to break up the text and also to give us an understanding of what happens.

Finally, your glossary needs a fair few more words in there as to help with our understanding. You have many references which is great, however take a loot at 46 – 49 – they all seem to be the same? It would be appropriate to merge them into one reference.

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The text on this page is very good, detailed and to the point. However a lot more images are needed on the page to make it more appealing, interesting and easier to follow.

The section under Ocular Manifestations is a little difficult to keep track of, there needs to be more of an introduction in that section highlighting the two sections that are to be discussed, then there should be a clear division between the two.

Also the placement of the few images on the page need to be organised a little better. The referencing on this page is done very well and its good to see an extensive use of resources.

I really liked the way how sub-divided the different abnormalities in vision and matched them with the corresponding image. However, further headings would be better for finding specific abnormalities especially when it comes to genetic causes. Also, the addition of normal eye functioning summary is a good recap on the eye before getting to abnormalities.

The molecular pathways are a bit hard to follow and confusing, although interesting.

The images are great and balanced with text, but the set out needs to change to make it more “friendly looking”.

Your glossary is good but may need a few more additions and extensive references are excellent.

Summary: overall very good and not complaints besides maybe think about the setting of the text to pictures.

Good luck with the rest ☺

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- A very good start to the page with the introduction. It gives an overview of the page and is very nicely done --- an image in the beginning will make it more effective. Right now the starting is very text heavy so an image will not just tone it down but will have a more profound impact.

- Normal eye development is good too but just to make the text look not so heavy you can consider putting it in a table like a brief summary.

- Traditionally research timeline should go on the top of the page but I don’t think it’s a big issue. Again you should consider tabulating it so it looks not so text heavy.

- I like how you talk about each part of the eye and different genes. You have a range of articles which also seems great and shows how much effort you have put in.

- Research section is not so extensive so far so you might want to work on that.

At the moment the organisation of the page is not great and it is very text heavy. Even though there are many images on the page it still looks very text heavy. Adding tables might help breaking that up and also add make the page look bright.

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The information that is present on this page is fantastic. However, i think the layout of the page inhibits your ability to access that information a little bit. Large sections of information go unbroken by images/tables/diagrams. This strains the eyes a little bit, making it a bit of a chore to read the page. Try and include a few more images, even if they are basic. In other areas however, the images included break up the page too much, creating large white areas, detracting from the pages presentation.

There also seems to be disunity in how the different sections are formatted in regards to paragraph headings and lists. This may just be a product of teamwork and assigning different people different sections to do.

However, one important thing is that I cannot fault you for the information. It seems to be in depth, up to date, and with well structured referencing. The images you have included are well explained and referenced as well.

Overall, quite good :)

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As shown by your choice of sub-headings and research, the key points of your area of research are being addressed well! Your introduction flows well and gives a great overview of your page to the readers.
Due to the focus of your page being on abnormal vision, a more succinct effort should be made to introducing normal eye development. I suggest the use of a student made flow diagram in order to clearly present the information as well as satisfy the criteria of this task.

The approach to the abnormalities section is so far on a great track. I particularly like the separation between genetic and environmental abnormalities as well as the use of a lot of research to introduce interesting concepts and clarify the reader’s understanding. In saying this, it would be beneficial to organise images in this section in a consistent manner, to mimic the image ‘appearance of cornea due to CHED’.

Be sure not to include too much detail on the molecular pathways and proteins if not entirely necessary in informing the audience about the abnormality in development. This would help eliminate any concepts that are too complex to understand.

The placement of the timeline before the new research was a good idea as it gives the reader good background knowledge. I would consider condensing this into a table so that it is more easy to read.

Overall, a great page but it could be more easier to read if the information was organised in a more succinct manner such as in tables, dot points and flow charts. The referencing style is consistent and correct and there is a good balance between old and current research.

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"The introduction is good in the manner that it provides some brief background information regarding the normal development of the eye and abnormalities. Additionally, I liked how the introduction described the aims of the page because it sets up a structure for the reader to follow. Just make sure to proof read this section: “The development of the eye is very sensitive and REQUIRES accurate...”

In regards to the information presented and layout (outcomes 1, 2, 4 and 9):

1. Normal Eye Development: This section appears very well researched. I like how you referred to the stages throughout development. However, this section could be enhanced by adding an image of the normal eye structure and development – this acts as a reference point for your page viewers, allowing for a clear visual comparison between the abnormalities and normal structure.

2. Abnormal Development: I like the overview provided at the beginning as it sets the scene for what points you will be covering in this section. Great job. All sections are quite good, just perhaps include more images to further enhance your page.

a. Abnormal lens development: I liked how you first described the function of the gene in development and then stated any abnormalities that arise when the gene is not expressed or mutated. I liked how you included an image for the crystalline genes; just make sure to refer to the image in text (e.g. see fig. 1. or see accompanying image).

b. Abnormal corneal development: Similar to the abnormal lens section, there is a good explanation provided for each gene involved. Just some improvements: make sure to reference all information; e.g. No reference provided for “The ion transporter SLC4A11 promote sodium-dependent transport of borate as well as flux of sodium and hydroxyl ions. It has been shown that SLC4A11 is expressed in the endothelial cells of the cornea, and mutation of....”. The accompanying image has been referenced correctly and described, good work!

c. Abnormal retinal development: Once again, a great scope of research and information and suitable image. I liked how you described the impact of each mutation explicitly such as in Albinism “ganglion cells of retina decreased by 25%”. This really helps the reader to understand the extent of the abnormalities from certain gene mutations.

3. Ocular manifestations: the opening sentence is slightly vague. Could you please state which two separate sections that you are referring to? The section that follows could be better organised. It seems to jump from genetic issues to a research timeline then to future research on that disease to another example of a genetic mutation which produces abnormalities. I would suggest putting the research timeline shortly after the introduction and integrating research history not just on LCA but other abnormalities as well. However, the content for all these sections is well referenced and interesting to read. The balance between text and images between LCA and anopthalmia/micropthalmia sections is good and are both really interesting to read! I liked how you provided some epidemiological data and clinical manifestations in depth accompanied by suitable images. However, the environmental abnormalities section could use with more dot-point styles and images to enhance the presentation and aid in your descriptions.

In regards to peer teaching (outcome 5), this page was an absolute joy to read and all technical language was explained in the glossary. Just make sure to pay attention to those minor improvements. Good job!"

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Introduction gives an overview of your project. This gives structure to your project. The introduction is a little too brief. It would be nice to add some detail about the significance of eye abnormalities:
* how important is vision to humans
* how does vision abnormalities affect people
* how many people are suffering from major eye abnormalities, etc.

Great images. They highlight the severity of abnormalities associated with vision. It would be nice if you can make the images a little bigger or add more images. it just seem there's too much text and not enough images to break it up.

The normal development section is succinct and give sufficient background information so readers can understand the abnormalities section. It would be good if you can put this normal function part into point form or table. for example, 'stage...development'

The gene mutations section is very complicated. Maybe talk about the FOX genes and Pax6 genes in abnormal lens development and not as a separate section. This is so readers can associate the mutation with the disease immediately, without having to scroll to the bottom to find the consequences of such mutation. The layout makes the disease and gene section hard to understand. Maybe set it out as:
* Genetic mutation
* diseases from this mutation
* clinical symptoms of diseases
* treatments for the diseases

Most of the images are well referenced, except Albino Fundus image. for this image, you need the PMID reference style.

References 45-48 should be placed as one reference.

--[[User:Z3332863|Z3332863]] 17:26, 23 September 2012 (EST)

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Your introduction is quite short, but it does state what you will be discussing on your page. You might want to include the normal development in the introduction, to allow for an overview of what normally happens before you actually start on the abnormal development. It just seems a little odd that you have abnormal vision as you title and then almost immediately after that you have a normal eye development heading.

I really like the chronological order used in the normal development section. It might be a bit easier to read if you use dot points. References seems to be fine, however, 4 and 5 are the same. It might also be useful to create a link to the group page on normal vision development.

Abnormal development consists of a few subheadings. Personally, I would delete the lines below the different subheadings. It will make it look more like one section on abnormal development. I think it was a good idea to look at the different parts of the eye related to abnormalities – lens, cornea, retina, etc. You look at different genes which play an important role at a certain developmental stage and you explain the resulting effects. I can see a lot of research has been done on this section. Images will need to be made bigger. They look insignificant with this size and it just seems like the text is going on and on. A lot of terms mentioned in this section are not included in the glossary, eg. Dysgenesis, substantia propria, CRX (what does it stand for?). Please add these in. Again, check your references, because some are the same, eg. 8 & 9.

Ocular manifestation is part of the abnormal development section (I think), so please make sure you show this with the headings. Again, immediately below this seems to be another heading with genetics, which has nothing included… or does LCA belong to genetics? I am a bit confused due to all your different headings and lines which seem to separate parts that may potentially belong together.

In your LCA section I would change the order of text a little: definition (as you have at the start), then epidemiology (which you have at the bottom), then the section on Dr Leber (up to “…placing great emphasis upon the high incidence of hereditary factors.”), lastly a new paragraph on the diagnosis (“As stated in the section on… diagnostic protocol for LCA”). The link to Abnormal Retinal Development does not work and will need editing. I can see that your timeline refers to LCA in particular and it is quite expansive. The one reference provided leads to a website with a timeline that seems to have been copied and pasted into your project. Please change this into your own words and (where possible) provide references to the original papers. The table also seems to be located in a strange position and it may be better to include this information in a table on history (in general), which you do not have at the moment. New research development also focuses on LCA only. Maybe create a separate section at the end where you can mention this and include more current research in brief paragraphs. The image relates well and has the appropriate citation, copyright and student template. The description could include a little more information.

Anophthalmia and microphthalmia are other genetic abnormalities described. Again, with the image you can expand slightly upon the description, but besides that it relates well to your text. Information provided is good, and includes the clinical description, genetic causes and management. Most important is that you use the same layout for your headings throughout your project. Within this one section you are using different subheadings and it all looks a bit chaotic and makes it less encouraging to read. You explain the role various genes play and I would like to know at what week/gestational stage they are important and can cause these abnormalities. Make sure all your references are correct, eg. There is no reference for 30.

It is probably good you only focused on 2 abnormalities caused by environmental factors. Images could really complement the text (although your whole page could probably use a few more images), so please add these. You include some relevant information and statistics, but make sure you also keep adding to the glossary. References are also the same for 45-48, hence these need editing.

In my opinion, firstly change the layout of your page and make it more organised with logical headings. Then focus on some of the other things mentioned above.

Hope this helps!
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Your introduction is relatively well written and the brief explanation of new terms such as microphthalmia was particularly useful. Perhaps it would be possible to break the text into two paragraphs to make reading easier.

It is really good to see a section included about normal eye development as it provides a basis of understanding for the remainder of the page. Concise and to the point and not too complex, it's great. Only suggestion would be to place it in a table perhaps with each Carnegie stage a new entry.

Layout of abnormalities is very logical covering the main areas of developmental abnormalities. However it is slightly confusing that immediately under the title Abnormal Lens Development more information on normal development is given. Allocating the defects to their associated individual genes is good but perhaps instead of a dotpoint a subheading would be of more use. The actual information is clearly and effectively written. The inclusion of the pictures clearly illustrates the abnormalities but their placement is a little odd. Perhaps they are too large. The captions on the pictures are appropriate and the pictures are appropriately referenced and it is great that the link to the picture contains more information.

Under the title "Ocular Manifestations" perhaps indicate what the two sections are, just so the following on sections make sense and don't appear disjointed. The sections on the genetic caused abnormalities is fascinating and very well written. The timeline included in the information about Leber Congenital Amaurosis is particularly interesting. The spacing in the section on genes associated with Anophthalmia and Microphthalmia appears slightly strange. The figures included are particularly illustrative and appropriate. Similarly the section on environmentally caused abnormalities is really well written and interesting.

Perhaps a more extensive section on current research could be included. If possible, link the words in the glossary to where they appeared in the text. This is the coding if you don't have it [[#Glossary|'''Words for Glossary''']]. Just add that in place of the word when you first mention it in the text. The citing and referencing is really well done. It also shows a great depth of research. The figures/photographs so far included are brilliant but the inclusion of a student drawn diagram somewhere if possible would be effective. Also try and fix the general layout of the project, possibly including some more subheadings. In general the content relates to the the course and is pitched at an appropriate level. Hope this helps.

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The introduction was okay, however avoid referring to the rest of the page within the introduction - it should stand on its own.

Normal eye development is very succinct, however maybe consider adding an image here to aid with your explanation.

The abnormal section is very good and well researched. The images included are good, however as with the introduction, avoid using language such as "in the section below, we have focused on..."

The ocular manifestations section is very good but just needs to be organised better, the headings are somewhat confusing. Good use of images, timeline, and subheadings for different genes. The management section is also very interesting and can be elaborated on.

The glossary is good but the formatting can be improved - perhaps putting the key terms in bold or at least making all the terms italic rather than half and half.

The reference list is extensive which is good, but don't forget to add to the external links section.

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The differentiation between genetic and environmental abnormalities is an excellent idea and stood out immediately. This differentiation adds on to the organisation of the page and allows the information to be read with ease. However, the inclusion of tables and flow chart would go well in the page and make the information easier to follow. In addition to this, it would be great to see a few external links to make the page more engaging and guide audience to more more detailed information about certain abnormalities.

The information included is very extensive and highlight a great level of research. However, some of the information seems to be quite complex and difficult to understand. It is fine to cover difficult to concepts, but try to expand on it to allow for people to understand it or provide external/internal links which would provide more information and make the content easier to comprehend.

Having explained the function of genes in development and then explained any possible abnormalities that can arise in abnormal lens/corneal/retinal development made the information much easier to grasp. It allowed the information to flow and and the text seemed to follow a logical order. The inclusion of images in this section is great, whereas more images/diagrams is required for the rest of the page.

Covering the normal development is important and the chronological order used makes it easy to follow, however, keep in mind that there is a different project solely on normal development and therefore try not to expand to much about this topic. The referencing seems to be correct, and it is great to see a large range of sources have been used. One section that will require some work is the current research section as it does not seem like there is enough information. Apart from the issues raised, this page seems very promising.

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*'''Introduction:''' The introduction is quite well written and very detailed. Rather than going straight into details of development, perhaps first make it clear from the exactly what this project page is about and what content you will be covering. There are also some grammatical errors, such as “treatments or cures ‘’’maybe’’’ developed in the future and these conditions can be better managed.” Maybe = may be
* '''Normal eye development:''' This section shows a good depth of research, is strongly related to the aims of the embryology course and shows a good depth of research. Improvements could be made by the use of bullet points, tables or bold text to highlight key points. Also, labeled images or hand-drawn diagrams would go well to compliment the text.
* '''Abnormal Development:''' There is a good depth of research and it is well written. The use of headings, figures and italics makes it easy to follow the flow of information. Improvements could be made by providing more information about the diseases, for example, what is Peters' anomaly (Corneal Opacity) and aniridia (lack of Iris)? Is it curable? What are methods of detection? How will it effect the future baby?
*'''Ocular Manifestations:''' This section seems incomplete; or maybe its just poorly organized? What are the two separate sections? Is this related to the sections that follow?
* '''Research Time line:''' This is a good time line, however only one source has been used. This provides a good summary of significant discoveries, but it has not been explained why these discoveries were important or how it is relevant to the development of the eye.
* '''New Research Development:''' This section is well researched, however the poor structuring and layout of the information makes it difficult to read and follow. For example there are many headings and subheadings however it is unclear what sections of information are grouped together. The images draw the readers attention and there seems to be a good depth of research into the topic.
*'''Group Assessment Criteria:''' The key points relating to the topic that your group was allocated are clearly described in the introduction. The choice of content and depth of research shows a good understanding of the topic area, however the information could be better organized by the use of tables, bullet points and bolded text to highlight key points. The content is correctly cited and referenced. Most sections are well paraphrased for teaching at a peer level, however the use of hand-drawn diagrams and/or labeled images could enhance the information in the text. The information covered is strongly related the the learning aims of embryology.

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It was very good to see that this interesting topic has been well researched and that there are a number of references appropriately cited in the page.

Currently, there is a lot of text that, I as a reader, felt overwhelmed when assessing. More/larger images may need to be uploaded, or the correct formatting/resizing of existing images in order to potential rectify these concerns. It is noteworthy, however, that the ratio between text and imaging improves toward the bottom end of the page.
It was good to see that there was all relevant summary, referencing and uploading information for the images that were present. Keep in mind that there is an option, and we have been encouraged to upload images that have been student drawn.

The over all formatting of the page, besides being packed with written information, had a couple of spacing issues, from extreme spaces between the bullet point genes and consequent descriptions, in the ‘abnormal lens development section’, to virtually no singular spacing between the research timeline. in the ‘Genes’ section.

A way to aid to the above so that the page potentially is more visually appealing, is to place the genes and subsequent function into tables, or even placing the timeline information in a table form, or adding originality by actually placing this information on a timeline generated by one of the group members.
Overall though, I found that it was a very engaging topic and page presented.

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Group 5- abnormal vision

-content of introduction is good and immediately puts the page in context. Emphasises abnormal development. Perhaps reconsider the syntax of some of the sentences

-paragraphing throughout project needs review

-a picture near the beginning would make the page more engaging. Seeing you can't talk too much about normal eye development, it might help in conveying some information

-you frequently make use of the carnergie stages, which is great, but perhaps briefly describe what this system means

-it's good that you have contrasted normal and abnormal development for each structure, but make sure the information isn't repeated in the "normal development" section, or perhaps remove that section altogether

- info about what the different genes control is good. What does "the first embryonic days 8.5" mean?

-I assume the two separate sections in "ocular manifestations" are genetic and environmental, but because they're not stated in the intro of this section and there's so much information in-between, it's difficult to tell. The formatting of this section adds to the confusion. Keeping the information and formatting consistent for each abnormality will make this easier to follow. The appropriate heading, sub-heading etc formatting needs to be used as well

-I like your case study, it reminds us of how these problems effect real people

-no current research or external links section?

-excellent use of resources

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Introduction is sufficient for now, but it may be better if you add more details, with more references, and perhaps an image to support it. Maybe an image of the eye and its structural components labelled, with functions explained in the caption.

You could add some images for the normal eye development.

Ocular manifestations section needs more work. It is good that you have added appropriate referencing for the information posted so far. Add more details in clinical manifestation, as it is difficult to follow. Add some images to support the text, especially in the research timeline.

New research development section is very well done, it is very detailed and has a good balance of text and images. But your images needs more description in the image details.

When you are talking about the genes such as PAX6, OTX2, RAX, it would be good if you format it to make it bold, and add them to the glossary section.

The glossary is very lacking, it needs more words.

The reference section is good so far and has correct formatting. However you have repeated some of the same references a few times. You need to fix that.

There are no external links listed as of yet. Please add some useful external links.

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Abnormal Vision

An excellent straight forward introduction, presentation and layout of the page is questionable perhaps the use of different summary methods would improve this for example dot points along with image choice and size. A common topic among all groups is to expand the glossary which is easily done and will only improve the finished merchandise. Language used throughout could be less primitive, very simplistic in certain sections. The referencing is satisfactory although external links section has been left out.
All the information is present although the organisation skills need to be assessed to allow optimum presentation of ideas. The text contains in-depth embryological teachings aims. The page looks promising and editing is the easiest part once corrected I expect a sound result.
--[[User:Z3330795|Z3330795]] 09:54, 26 September 2012 (EST)

==Discussion==

Hey so what organ did everyone decide on heart or liver.
I vote for the Liver

Hi Team! I would first like to apologize for not coming on Wednesday on our practical. So I am sorry one more time for that. I am coming to practicals this Wednesday so we can discuss our topics. Just to ask what happen on Wednesday in regards of our group project? So we need to decide between heart or liver to write our project? If that is so...I vote for the heart then:)

'''remember to sign after contributions to this page'''

Hey kidlings, just to let you know, I'm going to be looking through my path/grey's anatomy textbooks for anything i can possibly find.
I think we should start with a little intro of what is the normal development and then have some abnormalities that can stem from that?
Thoughts?
--[[User:Z3374173|Z3374173]] 19:17, 21 August 2012 (EST)

Hey Team, some ideas for the focus of our topic. 1. a basic overview of the development of the eye, 2. divide the eye up into it regions of development and look at the abnormalities that can occur, including the factors which make it abnormal: congenital or defect; percentage of occurance in society and/or likely hood aquiring it; processes of the abnormal development (how abnormaility occurs); living with the abnormality; any treatments and/or prevntions for the abnormality.
--[[User:Z3220343|Z3220343]] 19:31, 21 August 2012 (EST)

Possible sources: [http://www.sciencedirect.com/science/article/pii/B9780750673365500098]
[http://www.sciencedirect.com/science/article/pii/B978032302394800019X]
--[[User:Z3374173|Z3374173]] 10:12, 22 August 2012 (EST)

Textbook: The Developing Human Chapter 20 [http://www.mdconsult.com/books/page.do?eid=4-u1.0-B978-1-4377-2002-0..00020-5--s0015&isbn=978-1-4377-2002-0&uniqId=352694541-2#4-u1.0-B978-1-4377-2002-0..00020-5--s0015] --[[User:Z3220343|Z3220343]] 10:14, 22 August 2012 (EST)

Looking through textbooks, I have found Retinoblastoma which is a tumor usually in the posterior retina. It says it can occur in 2 year olds but also can occur at birth, so that could be a developmental one. I found that in my pathology textbook, Others i found could be Horner's syndrome, that apparently can start developing in fetal development. I'll go through my mums old midwifery textbooks too. Anyone else find anything?--[[User:Z3374173|Z3374173]] 16:49, 26 August 2012 (EST)

Hey so i was looking through the textbook and i found a list of defects of the retina. further down it also talks about congenital glaucoma. [http://www.mdconsult.com.wwwproxy0.library.unsw.edu.au/books/page.do?eid=4-u1.0-B978-1-4377-2002-0..00018-7&isbn=978-1-4377-2002-0&uniqId=355501465-2#4-u1.0-B978-1-4377-2002-0..00018-7--s0015]
i found this while surfing pubmed may be of some use?[http://www.ncbi.nlm.nih.gov/pubmed/20933211]
i had heard of a genetic disorder in which if both parents are carriers the baby has 25% chance being born blind. i think this was the disorder if not, it still could be interesting for our assignment [http://www.blindness.org/index.php?view=article&catid=38%3Aother-retinal-diseases&id=253%3Aleber-congenital-amaurosis&option=com_content&Itemid=88][http://www.ncbi.nlm.nih.gov/pubmed/22842231][http://www.ncbi.nlm.nih.gov/pubmed/22842230]--[[User:Z3220343|Z3220343]] 21:09, 28 August 2012 (EST)

I think I shall do Horner's Syndrome. [http://jtcs.ctsnetjournals.org/cgi/content/full/120/2/419]--[[User:Z3374173|Z3374173]] 11:29, 29 August 2012 (EST)

Hi team :D I just found an article that talks about all the current knowledge on conditions related to abnormal visual development in infants. In the article, they have aslo included prevalence, risk factors and mechanisms that are involved with the development of these conditions. I think it would be quite useful to our own topic. Just letting everyone know, i will be doing congenital cataracts. [http://www.ncbi.nlm.nih.gov/pubmed/21478704]--[[User:Z3331330|Z3331330]] 12:36, 29 August 2012 (EST)

Heres another article description of the normal visual development, each component of the visual system is included and explained very clearly, this would be useful for our general overview on the development of the eye. In particular, the retina development is also mentioned in the article which we can make use of when comparing our disorder with the normal development. [http://www.wonderbabiesco.org/UserFiles/File/Graven%20and%20Browne%20Visual%20Dev%2008.pdf]--[[User:Z3331330|Z3331330]] 12:47, 29 August 2012 (EST)

Hey Guys, After trawlling through stacks of info on Horner's syndrome I'm not satisfied with the amount of info there is so I'm going to change it up and try Chorioretinal Scars. I can find more information and really hope this comes together!! --[[User:Z3374173|Z3374173]] 21:34, 10 September 2012 (EST)

I did the normal development, feel free to check it over, make changes etc, I have the PDF files of the articles i used if you need to check. Also, I've forgotten how to make all the reference bind together if they are the same text, i cant seem to find the help to help me so I'm just going to leave it until someone can help me!
--[[User:Z3374173|Z3374173]] 17:07, 12 September 2012 (EST)

hey team, do u guys think that we have enough information? what else should we add in if we do need some more.--[[User:Z3331330|Z3331330]] 22:00, 17 September 2012 (EST)

Talk:2012 Group Project 4

2012-09-26T00:04:38Z

Z3330986: /* Group evaluation */

{{2012GroupDiscussion}}

--[[User:Z8600021|Mark Hill]] 09:59, 18 September 2012 (EST) This is a recent review on smell. http://jcb.rupress.org/content/191/3/443.full JCB content allows reuse.

Not for reuse but good reading - [http://www.ncbi.nlm.nih.gov/books/NBK55980 The Neurobiology of Olfaction]

==Group evaluation==

The project page was exceptional, there is a fine combination of text and images and the images are well integrated with the presented information. I particularly like the inclusion of a hand drawn histological section embedded within the table of historical findings. Perhaps this could also be done in the next table about the developmental timeline. As it stands, this table, while detailed in its wording may be difficult to understand as there are no diagrams to show the differentiation in visual terms, from week to week.

The clinical features, anatomy, and pathohophysiology were excellent. There is not much more to say. All of the diagrams were properly cited with correct copyright information. The CT scan was also interesting to look at.

One aspect that hasn’t been touched on is future research. The current research section was very detailed and explained the significance of each new finding however as is the nature of research, there are always gaps left in our understanding or further questions that need to be resolved as a result of new information. A brief section on this would give the project more depth as it would show a level of critique rather than simply the presentation of fact.

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Your introduction is good and concise giving a simple understanding of the olfactory system. Here I would suggest that you include what you’re about to discuss on the page. I also think you should include some references and maybe a photo in this section. The references to show that this information has been researched and the photo to break up the text and give the reader a simple understanding of the olfactory system.

The history of discovery section is clearly well researched and is well set out. However, I would suggest that you include brief descriptions of what has been described such as the Vomeronasal organ or the Nobel Prize which will further enhance the readers understanding. You have a good use of references there as well. In the picture that was included in this section, I would provide a more indepth description of what is drawn i.e. what the ectoderm is etc.

The timeline of developmental process is really well set out and easy to read. I would just make sure that every new point you include, you put it with a references as some of your points are not referenced at all and you need to be careful of that! I would also suggest that you put it in appropriate bullet points using the star key on your keyboard, that way it can be set out a bit better. Also, at the end of week 8, does this mean the olfactory system is complete by then? If so, then I would suggest you state that in that final week, if not, then what other small changes occur throughout the duration of the pregnancy? Also note that week 6 – 8 the references are either limited or not there, so I would recommend putting them in.

The anatomy of the olfactory system and the normal function are limited in information but also have only one reference between them. The images attached should really have more of a description when the picture is enlarged to give the reader a better understanding of what you’re talking about. Such as: diagram of olfactory bulb- what does it do and where is it located?

The abnormality section is rather indepth for 2 conditions, are there any other factors that come into play in regards to olfactory defects? Such as environmental? The Kallmann’s syndrome is really indepth and describes the clinical features, diagnosis and treatment, could this also be implementd with the Choanal atresia? Or are the same techniques used there? Also, be careful when you use shortening of words such as OB, you provided the HH in brackets first, so I would suggest the same is done with the olfactory bulb just to prevent confusion. I like your use of both images and give s a simple but good explanation of what you have been discussing (and also breaks up the text!). I like how you have provided a good description in the enlarged picture and it makes it easier for the reader to understand.

The current research section really shows that you have put a lot of effort in for this section. However, at the beginning of each new research you state either a study or a paper with a link, perhaps use the name of the paper and who wrote it and use that as the link instead. It is really interesting and I rather enjoyed reading it, however, if possible I would add some more photos just to break up the text. Your glossary is good and well set out and the information displayed is quite easy to understand, however I would consider adding to this section as there were some other words throughout the page which were in need of a slight description. You have an excellent use of references which is great, but I would have another look at reference 11 as there is no text, only an arrow.

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The work needs to be spell checked before you submit it, make sure you get all your grammar right as well. I think you should add more to your introduction, and make it a little simpler, easier to follow. Also throughout your project you tend to use a lot of long paragraphs, especially in the current research section.

Though the developmental timeline that is set up is very detailed, it can be a bit hard to follow and a little confusing. There is too much text and no pictures at all to help demonstrate what is being said about the development. The ratio of images to text in the anatomy and abnormalities sections however is very good and makes it more interesting to read.

It’s good to see that you have some external links put up on the page and also that you’ve used quite a few references to do your research rather than just a few.

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WOW! I really can’t come up with anything bad to say about this wiki.
Text and image are nicely balanced.
Developmental timeline was very easy to follow and succinct which is always nice.
It was good to have research images alongside hand drawn images.
Diagnosis and treatment sections may need some expantion.
List of references current and varied – always good to see.

All in all this was a very good project and congrats of the good work. Keep it up.

Good luck with the rest ☺

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- The introduction is very good and brief --- although it does not tell the reader that it is about development of olfactory sense.

- The history section is immaculately done --- You have used a couple different sources and gone into enough detail about each historic background which tells me that you have thoroughly research this part.

- The development section is also very nicely done --- I like the layout of this section. Also the sentences are very clear and structure is easy to follow. There is a large section in week 6 which does not have any reference so you might want to fix that up. Same goes for week 7 abd week 8.

- When you start talking about anosmia it just abruptly follows normal function so you might want to add the heading “abnormal development”. It might even be a good idea to put normal function before normal development to put things in prespective.

- In Kallmann’s syndrome although it was very interesting to read, it is very heavy on genes which you have not addressed in the normal section portion. I do realise for some of them you have put a description as to what they do in normal development but see if you can integrate it with normal development too.

- It is also good to see that you have a diagnosis section and a treatment section too. It was very informative.

- Current research is well put together

Overall your project is looking pretty good….Just some minor formatting issues. The text is a little on the heavy side so some images especially in the development section will be good.

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The introduction was very interesting to read - 1000 genes related to olfactory system is amazing. The introduction isn't too long which is great. However, it would be good to include in text citations. Where did you get your information from?

The history section will look better if it was put into a table.

The 'Timeline of Development process' is excellent because it clearly presents so much information with respect to the time the differentiations took place. I can't wait to see the images though because some of the concepts were hard to understand without visual aids. For example, 'specialized areas in rostrolateral regions of head of olfactory placodes' - where is that on the embryo?

The normal function section was short. This is nice to see because this project is about development, not about the function. It would be good to include a diagram of the signaling pathway in this section, just to make it interesting.

The structure section needs a bit more information. Maybe put the olfactory bulb image in this section as it relates more to structure. You can also put some images of the cribiform plate in here too.

Abnormality section on Kallmann's syndrome was very well written. It had lots of detail, presented clearly in point form. Can you describe some of the other diseases in just as much detail as well? It just seems like Kallmann's syndrome is the main disease and there's not a lot of focus in other abnormalities.

In current research, 'the 'role of Odorant receptors' need to have some text and content in that section, not just the reference.

--[[User:Z3332863|Z3332863]] 16:58, 23 September 2012 (EST)

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Page is well structured. Tables and images break up the information nicely. Some of the images lack an in depth explanation of what they depict/represent when you click on them. I know for some of the images it might be hard, but i think it would make for a more thorough way of presenting the information.
Not to much a critique, but you spend a large amount of time and space on the abnormalities section. When combined with the current research section and the images, only about a third of your page is information on olfaction. An even less of it is on the actual embryology when considering the timeline of discoveries and introduction. Try and draw out the embryology section a little further, considering the context of the website and who would be visiting it.

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Your introduction is good and gives a brief overview of what the olfactory system entails. There were a few spelling mistakes, which can easily be corrected. Make sure you do tell the reader what you will be discussing on your page – development of the olfactory system and the particular subheadings you will focus on. The image could do with a few more labels for orientation, but besides that it complements the text and contains the correct citation, student template, etc.

The history section is good and quite extensively researched. Most groups will provide the history in a table, with dates in chronological order (to clearly show history and developing knowledge over time). This might be something to think about. I would suggest a ‘date – description – significant person’ type of format for a table. Good image, but it is displayed next to Pearson instead of Kollman. It is also difficult to see what it is and read the labels without opening the larger version, so you might want to increase its size slightly. Because this is a student image I would like to see the original – if possible provide a link to the Atlas of the Development of Man 2.
You should also explain what Kallmann’s Syndrome actually is, because this seems a little vague.

Your timeline of developmental process looks amazing and is enjoyable to read. Some of your words are printed in bold and link to the glossary. In one of your next sections the words link directly to the glossary, so you should probably do he same thing here. I really hope you can add pictures to this table to complement your text! Not quite sure what the line at the bottom (SINUSES:A:…) is doing there… either delete or expand upon this.

Structure: you only have a link here. Please provide text and image to explain the structure briefly. The YouTube link should be there to help the reader understand this section, instead of being the only thing this section is made up of. The video is not your own work, so please add your own work to this!

The normal function section was alright. It has some useful information in there, however, only a single reference listed at the end. It seemed like more references should be included within the paragraph. I would also include the fact that depolarization is an all-or-nothing response. The threshold needs to be reached for depolarization to occur, but there is no build-up over time to reach this threshold. It has to happen at that one instance. The links should be listed under the heading ‘external links’ or, if used as references, incorporated as proper references within the text. The olfactory bulb image is a little small and the description is quite brief. Though, good citation of the source and a student template is present.
I think the olfactory bulb image and the epithelium image should be included in the ‘structure’ section.

The abnormality section includes Kallmann’s syndrome and a quick definition has finally been provided! Please include this in the history section too. This section was a joy to read! Very interesting! A lot of effort has been put into the research and references have been done very well. I assume OB stands for olfactory bulb – please indicate this in the text. The dotpoints listed in the ‘clinical features’ section could do with a brief explanations instead of me having to scroll up and down between the text and the glossary. The image is excellent and shows a good simplified concept of what happens. Good descriptions, source citations, etc are added too. It was good to see diagnosis and treatment included.

Current research starts with a link, which seems quite random – include this in the external links section. You found some interesting and current research. References are only listed at the end of each paragraph, but should probably be included within as well. The image relates to one of the projects and descriptions are appropriate. Nothing has been added to the ‘role of odorant receptors’ though (apart from a reference). Please add a brief paragraph to this section.

Terms should be added to the glossary. The reference list also needs checking, because some are the same (eg. 11 & 12) and others do not have a reference (eg. 7 & 17).

Hope this helps!
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The introduction is quite small but very precise, indicating the function and the components of the olfactory system but maybe include one or two sentences in the introduction telling readers that it is actually about the development of the olfactory system, not just the function and components of it. After all, introduction is meant to show others what your project is about. The hand-drawn image there is very nice but maybe more information need to be provided other than just labelling parts of it. Along with the image, there are the important informations such as the copyright notice which is good to see.

The history of discoveries section is very well-researched but it will be easier to read if it was in a table. The timeline, i thought was very good because there are a lot of useful information about the development of olfaction which relates to the research topic. The developmental process is explained in quite simple terms but i notice some of the scientific terms in the timeline are not explained in the glossary, this makes it a little bit hard to understand the whole process. It is very interesting that a youtube link has been included in the structure section, this is really a good peer teaching but make sure you referenced the video correctly to avoid plagiarism. The section on Kallman's syndrome is quite interesting but the structure of that section is a bit messy, maybe try clarifying and tidy it up a lit. But i can see that a lot of research effort has been put into it which is good and the variety of resources used in the section is very broad. More images should be put here because right now, there is just a huge block of text in the section. Images will balance out the heavy text load and attract readers more.

The current research section contains a lot of useful information and it relates to the research topic well. Again, images should be put here because right now, there are just small blocks of text in the section without any images, this maybe a little bit boring for readers.

Overall, the project looks well-researched and relates pretty well to the research topic. The balance of the images and text still needs to be fixed but in terms of the text and information on the page, i think it is pretty sufficient and in-depth especially the timeline of development and current research section. There are some terms in the glossary which is good but maybe more terms should be added. The structure of the page is good, very easy to follow. There are a few external links which is always good to put there for anyone that are interested by the topic and want some further information about it. Referencing is good, there is only one minor citing error (no.7), but it should be easy to fix. Hope this helps :)

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The introduction provides a good overview to the topic and the associated images have all the appropriate referencing information.

The history section is interesting and well researched with good use of subheadings.

The timeline of development is very useful and informative however is quite text-heavy, some diagrams may be able to help here.

The anatomy and normal function sections don't add very much to the page, especially in terms of embryological development. Adding more to these sections may help.

The abnormalities section is good, with a lot of information on Kallmann's syndrome, however other abnormalities (if there are any?) could be included to expand this section.

The current research section contains a lot of information in a small amount of space. It is quite jargon-heavy although this might not be able to be avoided. The subheadings are good as they act to split this section into discrete units.

The glossary and external links are very good, and the references are extensive which is good.

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* '''Introduction''': The information is very interesting and provides a good overview of the olfactory system. The only improvement that could be made is clearly stating what content is going to be covered on this project page. Also, “The olfactory system are often ‘’’divide’’’ into a peripheral mechanism”
* '''History of Discovery''': This sections presents a good summary of each research paper, detailing a background of the researchers and the importance of each discovery. Well done!
* '''Time line of developmental process''': This section shows a good depth of research and provides detailed descriptions of each stage of development. However, the information provided is quite complicated and would not be easily understood by peers. This could be overcome by the use of labeled diagrams or hand drawn images, which I can see is yet to come. Overall this is a well done section, the colors draw the readers attention and I like the use of bolded text to highlight important information.
* '''Anatomy of the Olfactory System & Normal Function''': This provides a good amount of information seeing as the focus of the page is about olfactory development, not the function & final structure. The only improvement could be providing an explanation in the figure provided.
* '''Congenital Abnormalities''': This section is well organized and includes all relevant content. Very interesting to read.
* '''Current Research''': A well researched section and coverage of content. Each paper is summarized and the importance of each discovery is made clear. It would be nice to include a direct link to each article.

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For me this is one of the best projects of the 6 groups. It is extremely well researched, as seen through the extensive reference list. It is evident that the group has gone above and beyond, researching even more than required for the topic, or standards set by other groups, such as clinical approaches, and much information on current research.

I found that the formatting in the upper part of the page, specifically the section under the title ‘normal function’ was a bit awkward in relation to text and image positioning. It felt that it was not consistent with the flow of the rest of the page.
Also the first table may require an in-filled colour or even lines (can be a light or pale colour), just so each column and the single uploaded image is more defined and linked to the correct year/individual.

The ‘Choanal Atresia’ tomography image requires acknowledgement that the image was uploaded as part of a university assessment. However, really appreciated the breakdown of where the arrows were pointing and the relevance in relation to your specific topic.
Images for the tables need to be finalized and uploaded; ensuring that there is appropriate referencing, whether they are student drawn, or sourced from the literature.
Found that the student drawn diagrams were really detailed and easy to understand and appreciate. Each was also relevant to the topics, which they were linked/associated to.

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The introduction while small gives a great overview on what olfactory is. You could add a small overview on what the page is about to make this part a little longer.

I like your table on development however there is some information in the table which is missing references, you should see to that soon and add a reference. Some images in this section would be nice and if there are not going in the table then you might want to delete the image column.

The anatomy of the olfactory system is quite small; this part could possibly be added to your introduction.
Kallmann’s syndrome is done very well and is quite thorough and as a result the choanal atresia section looks lacking. I would suggest adding this to the bottom of your abnormalities section and if no more information is going to be added to the page maybe state that other abnormalities include - choranal atresia and then maybe an external link.

Current research section is quite detailed and I would not add anything else to this section. I did notice that Role of Odorant Receptors is just stated with a reference and no information. If nothing is to be added here I would just delete this heading.
--[[User:Z3220343|Z3220343]] 21:33, 25 September 2012 (EST)

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Group 4- olfaction

-numerous typos and syntax errors throughout. My favourite is "naval cavity"

-generally well explained and I like how you've used different formats for each section to keep it interesting

-this seems a bit random-

"SINUSES: A: EFFECT OF AMNIOTIC FLUID ON THE DEVELOPMENT OF OLFACTION IN THE FETUS (current research in the field):"

-I think the anatomy section should come before the developmental timeline just to put the developmental stages in context

-abnormal function is very comprehensive :)

-current research is great, it appears some quality research went into this

-excellent use of resources throughout, including your external links. I think you've covered everything well

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Introduction is sufficient for now, but it may be better if you add more details, and perhaps an image to support it. Maybe an image of the nose and its structural components labelled.

History of discoveries section is great so far. You gave succint information with references. You only have 1 useful image in this section, so it would be better if you add more images.

Developmental timeline is very well detailed and has appropriate refrencing, however more refernces need to be added for some of thee information. You also need to add images as that column is left blank so far.

Anatomy of the olfactory system needs more details and explain the structural components. The diagrams are good, but needs more description in the captions.

“Congenital Abnormalities” is very detailed, with appropriate referencing and good images. It would be good to add a few more images. Also, add more description in the “Computed Tomography of Choanal Atresia” image.

Current research section is very good so far. Perhaps adding a few more images to support the other articles would make it better to read.

Glossary section is good so far, but needs more words to be added.

The references section is excellent.

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Olfaction review:

Upon first glance of the page you immediately get the impression excellent presentation and a surplus of information. Most topics are well described although the history of discoveries layout is questionable and a table would present at a higher quality.
It is clear that the group has a high level of understanding through large amount of research; this is then transformed into chunks of knowledge in which are easily digestible for the reader. The page lacks visual encourage, I believe more detail into this would only benefit the page. The glossary could quite easily be expanded many terms throughout the text are absent from this list.
This page is almost parallel with embryological teaching aims. Citation & referencing is excellent. The way to improve this page would be reducing the weight of the text using innovative ideas to the present information in a more exciting way along side inclusion of more visual stimulus.
--[[User:Z3330795|Z3330795]] 09:53, 26 September 2012 (EST)

== External Links ==

Hey team... make sure you check the links i added to the external link section. They are great resources to use in your sections.

[[User:Z3333427|Z3333427]] 10:19, 21 August 2012 (EST)

== Group Topic Selection ==

So we have a choice between:

stem cells

Neuronal development

Sensory development

I personally don't have a particular preference but I think neural or sensory would be something different to touch on since there's still so much progressing research in the field.

'''Hey all :-). Thanks for getting the ball rolling. I like the latter two options, in particular neuronal development - from there we can pick a certain aspect and explore not only normal development but perhaps research complications and genes/factors implicated when things go wrong.
p.s. It would be great if we could figure out a regular time to meet during the week outside the lab so we can properly discuss and share our research'''

Just a heads up- Mark preferred that we don't put our names up anywhere on the wikipage for privacy purposes!

'''sensory system'''
hello everyone, it seems like the options we had chosen for sensory were picked before we had a chance and therefore I have asked Dr Hill for us to do the "hearing" system. I don't mind changing if the group chooses to do so, however, I thought it would be a good idea to have a topic locked in. Please let me know if you want to do a different topic

--[[User:Z3333427|Z3333427]] 11:32, 14 August 2012 (EST)

=Designation of parts=

There must be an addition of current research and technologies in each area

Make sure this is not presented as an essay (balance text and writing with images, tables etc)

Possibly a history of the development of understanding

[[User:Z3331264|Z3331264]] 11:54, 15 August 2012 (EST) Timeline and processes of development

--[[User:Z3374215|Z3374215]] 11:59, 15 August 2012 (EST)I would like to do a history section and the introduction

Please identify which part you want to be responsible for, keep in mind that you can work at any topic you would like.

Introduction: Andrew

History: Libby

Abnormalities: Stephanie

Future research: Libby (future research on normal function) Stephanie (future research on abnormalities/treatments)

Timeline: [[User:Z3331264|Z3331264]] 20:18, 22 August 2012 (EST)

==Progress of individual tasks and project queries==

[[User:Z3331264|Z3331264]] 20:18, 22 August 2012 (EST): I will be creating a table to indicate the timeline of development of olfaction during embryonic development. I will make changes to the initial table as I go along so as to avoid not contributing any online material until the end.

--[[User:Z3333427|Z3333427]] 00:58, 25 August 2012 (EST)The table is a really good idea, we should probably have at least another one as information becomes much more organised. Just to let you know that I changed it to Carnegie stages as most sources organise their information based on those stages, and keep in mind that the placodes dont form until week 11 or 12, so there is no need to have stages 1-10.

--[[User:Z3374215|Z3374215]] 17:52, 27 August 2012 (EST) I've got some information on historical developments but information is really difficult to find. I've made some progress but not sure how much more there is that I can do. In light of that I might also take a look at the subheading "Structure". It's referring to the physical structure of the developing olfactory system?

--[[User:Z3331264|Z3331264]] 19:33, 27 August 2012 (EST) Carnegie stages are a good idea! I also think its important to include a brief description of the development of the anatomy of the nose (turbinates etc) as well as a bit about the brain development in the locations of the olfactory nerve. Don't freak out when you read my additions, I do my research gradually, which means I will first add what I found in the textbook and then later on fill in the gaps plus add a research dimension with current lit.

--[[User:Z3333038|Z3333038]] 10:09, 29 August 2012 (EST) Hi all, you heard it from Mark today but just restating, even when doing draft work you must reference properly as you go along or you will be penalised.

--[[User:Z3331264|Z3331264]] 11:22, 29 August 2012 (EST) Decided to just stick to weeks rather than carnegie stages because sometimes between carnegies stages, little events occur which will make the table larger and more confusing!

--[[User:Z3333038|Z3333038]] 18:01, 29 August 2012 (EST) Hey Libby, I found a review article which contains a brief history on olfaction abnormalities in development in the introduction: http://www.springerlink.com.wwwproxy0.library.unsw.edu.au/content/288u546105v08575/fulltext.pdf

--[[User:Z3333038|Z3333038]] 19:26, 29 August 2012 (EST) Hi all, just letting you know im working through pathophysiology for Kallmann's syndrome on a word document at the moment and will post some as I go online to document progress. Currently working on a diagram demonstrating the abnormalities in the olfactory bulb neuronal connections.

--[[User:Z3333038|Z3333038]] 21:18, 30 August 2012 (EST) Completed my diagram and have uploaded it with referencing. I based my diagram on an image from a review article which I have referenced - have emailed Dr. Hill to check that all is alright in terms of copyright.

--[[User:Z3331264|Z3331264]] 22:25, 4 September 2012 (EST) : Hey everyone, this is the html code to add to your parts whenever you wish to place a link of a word to the glossary:

[[#Glossary |'''put the word you want linked to glossary here''']]

--[[User:Z3374215|Z3374215]] 17:18, 5 September 2012 (EST) Hi Stephanie, I found an interesting article about abnormal development of the olfaction bulb of mice when exposed to alcohol. Don't know if you'd seen it. http://www.ncbi.nlm.nih.gov/pubmed/21736737

I also read that article! Pretty interesting stuff

[[User:Z3333427|Z3333427]] 17:48, 7 September 2012 (EST) That is a good idea, please email Dr. Hill if you are unsure about anything as huge penalties apply for ignoring copyright. By the way our group project is looking good, more diagrams and tables similar to the one we have now would be great.

--[[User:Z3333038|Z3333038]] 08:21, 11 September 2012 (EST) Thanks for the article :-). I will add it to a section on congenital anosmia. I emailed him and he said it was absolutely fine, as long as I referenced my source information.

--[[User:Z3374215|Z3374215]] 12:00, 12 September 2012 (EST) Just a note to myself more than anything. I need to reference Julius Kollmann's textbook in the history section and add a diagram.

--[[User:Z3333038|Z3333038]] 20:12, 14 September 2012 (EST) Loving the page team! The drawings are great! Nearly finished my bit, just have to add a brief paragraph for the other congenital abnormalities and one more research article.

--[[User:Z3333038|Z3333038]] 22:35, 14 September 2012 (EST)Hey Libby I found this website for timeline/history: http://www.medlink.com/medlinkcontent.asp...it talks about discoveries of congenital olfactory defects.
--[[User:Z3333038|Z3333038]] 09:15, 15 September 2012 (EST)Completed abnormalities and submitted 3 current research articles. Happy to take on extra parts.

--[[User:Z3374215|Z3374215]] 12:06, 15 September 2012 (EST) Thanks Stephanie that site looks great! I'll check it out soon.

--[[User:Z3333038|Z3333038]] 11:06, 19 September 2012 (EST) Important! Hey guys, we really need to work on the development of each structure and the genes involved. Who can help me out?

--[[User:Z3333038|Z3333038]] 11:47, 19 September 2012 (EST)Note to self: Make section on external links.

--[[User:Z3331264|Z3331264]] 17:49, 20 September 2012 (EST) The table that I included walks through the timeline of development. I have slowly been adding more and more research including genes involved in patterning. But at the same time, I don't want to dive into too much information in order to maintain the balance between text and images. I have figured out a way to do this without making it all seem too simple, so just bear with me for the next week and you'll see it tie in well. Cheers

--[[User:Z3333038|Z3333038]] 09:52, 25 September 2012 (EST) I have stumbled across an extra abnormality - although it is more a structural defect rather than a sensory defect, it still relates to olfaction so I have added it in. Will keep it brief though as whilst it is a common nasal abnormality, it is not so much a sensory one. Also, Z3374215 and I are concerned - are you two alright with your parts? We know, like the rest of us you have other assessments but it's been a long while since we've seen any major contribution - if you're stuck we are happy to give you a hand.

--[[User:Z3374215|Z3374215]] 19:07, 25 September 2012 (EST) Hi guys, don't want to impinge on anyone elses work but I think I have to change a couple of generic features on the page. If you don't mind I'll just stick the external links in the section down the bottom with the others. I also may have to move or make smaller the initial image of the olfactory system as I think it is stopping a table from formatting properly. If you are unhappy with any of those small changes I make please feel free to put them back or let me know and I will. Cheers.

Talk:2012 Group Project 2

2012-09-26T00:00:53Z

Z3330986: /* Group evaluation */

{{2012GroupDiscussion}}

--[[User:Z8600021|Mark Hill]] 09:57, 18 September 2012 (EST) This is a recent review on touch. http://jcb.rupress.org/content/191/2/237.full JCB content allows reuse.

==Group evaluation==

The introduction is ok, there is an imbalance between text and pictures. Particularly there is a sentence which reads “The following picture shows the general organization of the somatosensory system” however there is no picture. Also in terms of sentence structure, there are four sentences in a row which begin with “the somatosensory system...” or “the system...” Try to alternate how different ideas are expressed as at the moment the paragraph reads as a disjunct of ideas.

As a whole the page’s visual appeal needs ameliorating. There is far too much text and only two pictures, one of which is very large and appears to be compensating for a lack of smaller relevant diagrams within the body of each section. Having said this, the neural development section was very well done. It was detailed without being verbose and showed it was well researched. The hand drawn diagram is excellent. The cell biology part was also very well written and well structured however again, it simply need some visuals to aid in some descriptions of molecular processes.

There appears not to be a continuous referencing style on the page. The introduction has in-text referencing whilst the rest of the page contains endnotes. A minor problem which could be fixed easily, though quite important nonetheless.

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I really like your introduction, I think that is is really informative and gives the reader a much clearer understanding of what this topic is about. Your references here need to be included in the reference section below but it appears that you have a good amount of references for the points depicted. At the end of the first paragraph it discusses a picture of the general organisation however there is not one there?? Also the inclusion of a picture would be agreat idea not only to further our understanding but also to break up the text and make it more appealing.

In your history of discoveries section I would probably recommend putting this in a colourful table, again to rbeak up the text, and also to make it easier to read. I would probably suggest here that you include a greater progression of discoveries to show the change of thinking over time. Note to also inlduce the appropriate referencing as shown in previous lab classes.

The central somatosensory differentiation is very expansive and informative. I would assume that you have put a lot of research into this section. Note that you have used pretty well the same references over and over. I would suggest that you include additional references to back up those statements as well. If those couple of references were the only ones saying that information, then I would suggest further researching to ensure that other journal articles don’t contradict this. The image is good and appears to show a good somatosensory pathway, however I would make the font bigger, so that it would not be imperative to enlarge the photo to read what is there. The picture has a discription when it is enlarged which is good, but I think it would also be appropriate to put the correct student information for the referencing.

In the Touch part, I noted that almost none of the text is refenced, which essentially makes the information listen invalid, so I would look into finding appropriate references here. Also, this section seems a bit dull with no pictures. Perhaps histological photos could be included here? I know we studied them in histology and this would make the section more interesting and also compliment the information stated. I would also suggest that those subheadings you don’t want in bold, you list in italic with two ‘ ‘ in order to separate it from the text below..

The Pain section probably needs to be set out better by using dot points? It appears that you have provided some excellent information but it is also important to put the references included with the reference section below. A photo here might be nice, perhaps of the different fibres if this can be found?

The Hot/Cold section is better set out and I like the appropriate referencing here. However, it appears that you are re-using the same references, so I would suggest some more research be done here to compliment your other references. It is better set out, however I would suggest some photos to be included if at all appropriate and can be found.

Pressure is similar to the pain section in the sense that the references really need to be put in the referencing section. It would also be advisable that you split the first paragraph up as it is rather long and not very appealing for one to read.

Current research section is good and concise. I like the use of the picture there, and I like the description that you have when you enlarge the picture. Is there any other current research happening now?

Finally, I would suggest adding more information outlining the development of these areas as I believe this to have been limited across the majority of sections. Although you are providing good reaseach and information describing these sections, as this is am embryology course, I would see it as appropriate that some sort of developmental progression is included – or if this is not known as of yet, for that to be stated. I would also highly recommend that you include a detailed glossary of words, as this is rather incomplete.

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Initial impression is it’s too textual for a wiki. The lack of consistent referencing styles is hard to follow.
Relates the developing somatosensation to the nervous system, which was good and very interesting.
Tables and mind maps/flow carts would be beneficial in sections 1.3.1-1.3.3.
And a section on abnormalities of touch would be nice and/or methods of detecting touch and pain etc (ie: clinical methods) and maybe sensitivity to touch.

However, the way this project was divided was logical and easy to follow. But more defined and succinct paragraphs need to be made as it tends to go on for a bit, but that is a sign of good research into the project.

In the section of thermoreceptors it would be better if there was an image from the article for graphical representation.

Summary: MORE IMAGES!!! Be more succinct.

Good luck with the rest ☺

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"The introduction is good in that there is a description of the role of somatosensory functions as well as an overview of its development. To improve further, perhaps avoid trailing off in the final sentence and perhaps put something that concludes your introduction.

In regards to the information presented and layout (outcomes 1, 2, 4 and 9), the history of discoveries is very brief and requires more research. Additionally, it would be useful to set up a timeline to add interest. The section on the central somatosensory differentiation appeared very well researched with a very interesting picture to accompany the text – good work. The section on Touch would better be placed in a table and have accompanying images to avoid getting too ‘wordy’. Also, this section does not have any consistent referencing in the bulk of the content – please cite where you find your information. The section on pain is well researched and has a strong content, however, to enhance this section I would suggest using dot points to describe the different fibres and add a relevant image. Similarly, the hot/cold and pressure sections were great in terms of content but could use with some dot points and visual explanation to make the page more interesting. Just a note on pressure – avoid getting repetitive; the page had already defined the Ruffini’s endings/corpuscles etc in the section of Touch. Additionally, the 2 urls at the bottom of this section are distracting, make sure to incorporate these in your reference list of add them to an ‘External Links’ section. Your Current Research section requires some proof reading and additional articles to make it more comprehensive. However, you have referenced the image well and referred to it in the accompanying text.

In terms of referencing, I noticed some areas where the in-text references were not correctly formatted and were in the (Author, date) style. Perhaps have a look at the referencing tutorial on the Embryology ‘Students’ page to get an understanding of the codes required for citations. For peer teaching (outcome 4), make sure that you define all technical terms – your Glossary only has 2 definitions provided. Other than this, the content overall is interesting to read just make sure you are striking a balance between images and text. Hope it helps and all the best!"

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- The introduction is small yet detailed --- I like how its an overview of the development. You do need to fix up the references though.

- You have in the intro section “the following picture….” But there is no picture there….if the picture is further ahead maybe write Fig 1 shows….and also label the picture.

- History section needs a bit work on – you should start with the earliest data and proceed in a chronological order so everyone can see the advancement in development of somatosensory organs.

- In the section of “Development of the primary somatosensory cortex” you have mentioned that there are intrinsic and extrinsic mechanisms --- you should mention what those signalling mechanisms are. Also if you are using the one ref for the whole paragraph do not put the ref after each line. Just put it in the end. Also it would be good to give the origin of the neurons like ecto, endo or meso.

- Its good how your description is divided into stages – it might help to give the weeks as well.

- For the touch section you have a lot of detail on what the receptors are which is fine but there is nothing about their development (which is what the project is about). The same thing is noted with “Pain” section – there is nothing on development. I’m sure you can put some genes or signalling molecules that are important for differentiation of cells into the different receptors.

At the moment your project is focused on what the different somatosensory receptors do but very little detail on how they develop, which is what you need to focus on.

More pictures are needed to break up the text.

Good luck!

--[[User:Z3333794|Z3333794]] 09:51, 23 September 2012 (EST)

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Overall, the key points relating to the topic area are being addressed. The use of current research to develop ideas and provide detail to the separate sub-headings is helpful. However, I would suggest better collaboration amongst team members about what is going to be addressed under each sub-heading because some repetition has taken place, particularly between touch and pressure where overlaps are expected occur.

Additionally, there is clear imbalance between text and images and there are some areas where dot points, tables, images or videos will be better received by the audience than paragraphs of information.

More specifically, the history of discoveries can be tabulated and should include more historic events that may have taken place before Weber and possibly led to his research.
In the section on pain, the bulk of the information can look more easy to read if the different fibres are bolded and put on separate lines with their accompanied descriptions or images or videos are used to replace the text.

A diagram or flow chart may be used in the hot/cold section accompanying or replacing the description on the sensation of temperature.

The section on pressure has all information cramped up in one paragraph which presents different ideas. I suggest each idea being put under a different heading or paragraph. For example, a paragraph on development, one on different structures and their functions (if needed since already addressed), one on research and applications. Images could be helpful!

So far current research looks promising and with the inclusions of more projects, would be interesting. I would suggest only including images in the research section when they can be simply understood and impact on the reader’s understanding or interpretation of the project.

The student diagram used in describing the somatosensory pathway is well done and makes a big difference to the page. The layout of this section is also organised and easy to follow and comprehend.

The references, although extremely extensive, is inconsistent between sections and a consensus should be met amongst team members, additionally, the glossary needs to be built upon. The inclusions of more definitions may help in limiting the text in each section.

Overall, there is no critique on the information presented on the page, it is all very interesting and current, however, a change in organisation of information will help bring this to the attention of the reader.
Good luck!

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Your introduction is quite expansive and the first paragraph gives an excellent overview of what the somatosensory system actually is. At the end of the first paragraph you do refer to a picture; however, there is no picture. Please add this to show the somatosensory organisation within the body. In the second paragraph you mention some key timepoints related to the somatosensory development, which is good. After this (“Development of the system entails…lemniscal system.”) the text is probably too specific for the introduction. This can be used as an introduction for your development subheading. Please make sure that you edit the in-text references to proper references which we can access via your reference list. Also make sure you start adding terms to the glossary, eg. dorsal column-medial lemniscal system (I do not know what this means!)

You have started on your history section, but it would be more interesting and easier to read if you put this in a table. For instance: date – description – significant person. Also try to add a few more important discoveries. Again, please provide proper references. See the ‘editing basics’ section on this embryology website.

The central somatosensory differentiation is good and I can see that a lot of effort has been put into this section. The picture is very helpful and complements the text. To some extend it does seem like the sensory neurons only come from the dorsal aspect (going into the dorsal root ganglion), so maybe put a note in there that the dorsal and ventral rami are mixed nerves and both of them will contain sensory neurons that go to the dorsal root ganglion. With this image, you also have to include the student template. Text and references are good in this section and I particularly found the ‘making connections’ section very clear, organised and enjoyable to read. Do make sure that you add to the glossary – in particular terms from the ‘development of the primary cortex section’, and if possible add more images.

The touch section has a fair amount of text, but no images to complement it. This made it a bit boring to read. Make sure the subheadings stand out by making them bold. Most of the text has not been references at all, which is concerning and could potentially indicate plagiarism. I also did not read anything about the development of the various receptors (or hypotheses it no distinct evidence has been provided yet). Keep in mind we are looking at the development of the system, not the physiology. You did put in some interesting facts, such as that cell abnormalities can lead to Merkel-cell carcinoma.

Pain and hot/cold are similar to touch: good description of the physiology, but no development included. References are only provided as in-text citations or listed below, which will need to be edited to include them into the reference list. Include images to complement your text and engage the reader – this also concerns the touch section.

The pressure section has limited information regarding the development. Please include how this develops – what factors are included etc. In my opinion there is too much focus on the adult physiology. We are studying embryology… As mentioned above, please edit references and include appropriate images.

Current research looks good with an interesting image and the appropriate references, copyright and student template. The description helps to understand the image. Maybe add another research project to this section.

Add to the glossary, references and actually name the external links listed as 1) 2) and 3).

Hope this helps!
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The introduction is very detailed and precise, and it really prepares the readers for what is going to be covered within the project. I thought it was a good introduction but the referencing needs to be fixed up because it looks really different too all the other parts of the project. I do not think that style of in-text citation is needed for the purpose of this project. The histories of discoveries will look better if it is in dot-points, it would be so much easier to read.

In the central somatosensory differentiation section, you mentioned that there are three components, but to me, only the primary somatosensory cortex has been extensively researched, i think more research should be done on the other two components. There is an imbalance of information between the three components. Also, I can see that only 2 references have been used in this entire section, maybe this is why there is an imbalance of information. Using a large variety of resources will definitely expand your knowledge and enable you to put in more information in this section. I thought the hand-drawn image was impressive but the colour is a bit vague and hard to see. A larger version of the image should be uploaded so that it is easier to see.

The "making connection" section has very good description on the physiology and the signalling process of CNS but I do not really understand the stages? Are they the stage events that are involved in embryonic development? Some more detailed explanation is needed here, and maybe some images will help?

The touch section has some good information but again only 2 references have been used which shows the need for further research. Images should be put in here because right now it is very crowded with text. Also, the same problem keeps occurring throughout the project, I feel like there are lots of information about the function of different components of the somatosensory system but not how they are developed. Make sure you do not go off track. There are some weird referencing in the hot/cold section which needs fixing up. There are nothing in the glossary, scientific terms and definition should be put here because not everyone will understand the terms used within the project page. The structure of the project was good though, very clear and simple which makes the page very easy to follow.

Overall, the page is looking good but maybe more research should be done and more images should be put in to balance with the large amount of text. Also, keeping the information related to the research topic will be a huge aspect to focus on. Hope this helps :)

Group Assessment Criteria:
# ''The key points relating to the topic that your group was allocated are clearly described.'' The introduction outlines the importance of the somatosensory system and provides a good summary of the developmental stages. More emphasis could be made on the key points of the project page.
# ''The choice of content, headings and sub-headings, diagrams, tables, graphs show a good understanding of the topic area.'' The content shows an understanding of the topic area, however the layout makes the text difficult to follow. There is not a clear connection between the ‘Central Somatosensory Differentiation’ and the somatosensory system. There is a lack of diagrams, tables and graphs to explain the written content.
# ''Content is correctly cited and referenced.'' Some sections are correctly referenced whilst others are completely lacking. This area needs working on.
# ''The wiki has an element of teaching at a peer level using the student’s own innovative diagrams, tables or figures and/or using interesting examples or explanations.'' The information is broken down well by headings and subheadings, however there is a lack of relating images to compliment the information. The one student drawn image is very useful.
# ''Evidence of significant research relating to basic and applied sciences that goes beyond the formal teaching activities.'' The information provided is well researched and satisfies the aims of the project in terms of developmental stages, however in order to go ‘beyond the formal teaching activities’ it needs to include sections such as abnormal development and more on the history, current and future research.
# ''Relates the topics and content of the Wiki entry to learning aims of embryology.'' The topics and content relate to the learning aims of embryology by describing the developmental stages if the somatosensory cortex.
# ''The content of the wiki should demonstrate to the reader that your group has researched adequately on this topic and covered the key areas necessary to inform your peers in their learning.'' There has been a fair amount of research into the topic, however a bulk of the information is focused on descriptions of each of the senses. More emphasis should be placed on the development of each of these sense as that is the key topic area.

Additional points:
* The Introduction and Central Somatosensory Differentiation sections were well written and the accompanying diagram was very useful.
* The layout of the page could be improved with the use of tables and diagrams to reduce/replace the amount of text
* The project seems largely incomplete; more research needs to go into the History and research sections and there is a lack of images

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Somatosensory review:

The key points are clearly presented at the top of the page efficiently formatted allowing viewer a perfect insight to the entire pages content. There is a severe lack of visual stimuli; this makes the page present as boring and text heavy.
Image citation is commendable although throughout the text there is unacceptable links to external sites that are not explained with a messy reference section. The information presented is quite detailed and promotes a significant amount of research and understanding, it is put forward in an excellent matter, sections that could easily be expanded are glossary, and perhaps a section specifically on development.
Attempt to relate to the learning aims of embryology are apparent. There is a large amount of information presented in a fantastic way although the lack of visual stimuli takes away from the final product, perhaps a more summarised presentation matter would be appropriate to break up large amount of text; this along with the tidy up of referencing needs to be addressed.

--[[User:Z3330795|Z3330795]] 10:36, 24 September 2012 (EST)

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The introduction provides a good overview however using the wiki in-text citation system will make it neater.

The history section has made a good start but this can be elaborated on further. Once again, referencing can be improved here.

The central somatosensory section has been well researched and the referencing is good. It would be preferable to label figures as "figure 1" etc as this makes it easy to refer to. The drawing is good and has a good explanation however the "student template" should be added.

The touch/pain/hot and cold/pressure sections have a lot of information on their function but not so much information relating to embryological development. Some sections are well referenced, other bits are referenced without the wiki format, and other sections aren't really referenced at all. This can be improved. Adding pictures to these sections to illustrate points will also be helpful.

The current research section, although small, is very good, well referenced, good inclusion of the figure however this could be given a name such as "figure 2". Adding more current research with variation in the topics covered will make this section even more interesting.

The glossary and external links are good - keep adding to these throughout the project.

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This page has made good use of subheadings ensuring that the main topics are easily accessible from the contents box. The project appears a little text heavy, it may help to include some other images. Also don't forget to add the student template note on the student drawn image. The reference list at the end is not particularly extensive. Perhaps this can be worked on by collecting the loose references in the text and adding them to the final reference section. Overall some sections of the page seem to have little to with embryology and more focused on adult function.

The introduction, while good, seems to lack any original voice, rather seeming to consist almost entirely of research done by others. The referencing in this section is also confusing with (Lagercrantz, Hanson, Evrard & Rodeck, 2001) being listed before any text. Referencing in this format also makes the page seem like a report or essay rather than a web page. There is also mention of a picture that does not exist. The historic section is brief and rather hard to digest as it is just a chunk of text. Perhaps putting this information into a table and developing it a little would help here.

The section on Central Somatosensory Differentiation was particularly well done. The inclusion of the student drawn image making all the difference. The general structure of this section is also commendable.

The subtitles "Touch", "Pain", "Heat/Cold" and "Pressure" are somewhat abrupt and don't particularly indicate what the section is discussing. This section in particular could do with the addition of some images. The information under Touch could perhaps be a little more heavily researched but is generally well written. Breaking the Pain section into some smaller paragraphs could be useful. The Hot/Cold and Pressure sections are well done excepting the random references to some articles.

Current research section could do with some more information. There are several words throughout the content that could do with being linked to an explanation in the glossary such as the "dorsal column-medial lemniscal system". The external links section is a good addition but it might be helpful to explain more clearly what each links to, especially the last three.

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The introduction for somatosensory is very informative and the overview of its development is great. The information is also great, however i do notice a bit of overlap throughout the page. It is important to go through the information and remove information that is repeated.

At times it feels like there is far too much information and not enough images, tables and diagrams. Dot points would be an alternative way to present your information as organisation is necessary. Including some tables and breaking up the texts into more subheadings would make the information easier to absorb.

The history section requires some attention, and it is important to put it in a chronological order.
A number of references were not cited correctly and this needs to be corrected. It is important that you refer back to the tutorial on referencing as the citations are very important. Your glossary needs to be worked on and extended, it simply does not cover enough words within your project.

Where is the development section? This is one of the most important topics in the project in addition to function which need to cover signalling molecules and genes. The section on pressure however, is great, but the information needs to be put into tables or under more subheadings to make the information easier to read. At the moment information seems to be all over the place.

The current research section is great and should be expanded upon. The self drawn diagram about the somatosensory pathway is very informative and easy to understand. The references are great but some are included more than once and these need to be organised at the end of the page.
Beside the limited diagrams, images, tables and organisation this page looks very promising. Good luck

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'''Somatosensory'''

Sectioning off the touch, pain, hot/cold and pressure was a very well thought out idea, but wouldn't hot/cold come under a temperature? Just an idea to change the heading to something a bit more formal. Overall the content was very well written. And most sections were referenced properly. Other sections were not, such as the introduction and pressure. The content in these paragraphs is so well written, I fell it is left down by the referencing problem. I found that there were only a few references used in some sections, and sometimes being only one. That may be because there is not enough information out there, I'm just not entirely satisfied with the amount of references. I feel there's more out there.
The hand drawn picture was very well done and I like it.
The Touch section was well done but had no developmental development, current research is lacking and as is the glossary.
There needs to more pictures also.

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The introduction is thorough and explains what your topic is about. The history of discoveries part if that is all the info you can find, why not put it in a table it would format the section so the reader can get an overview on how our understanding on somatosensory began.

Your page could do with adding some more pictures in relation to the different sections of somatosensory. for e.g. you mention Meissner's corpuscles in the touch section, you could add a picture with labels so that people could have a visual to understand, as you state where they are located but lay people would not understand what dermal papillae are.

I see you have an embryology and development part with no information, hopefully this will be added to in the near future otherwise don't forget to delete it.

You should also add more to the glossary and have a part called external links and place your links there.
--[[User:Z3220343|Z3220343]] 21:30, 25 September 2012 (EST)

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Your introductory paragraph is very detailed and has appropriate references. It would be nice to add an image to complement it somehow. Because it’s not very easy to read a big block of text without any image supporting the text. It would look more balanced that way. Also, providing clickable links to the references would be better and make it easier for users to find the original references by clicking on the citation rather than scrolling down and manually looking for the citation in the references.

History of discoveries section is somewhat lacking in content, you need to add more information. It would be nice to do a timeline format to make it easier to see the transition of new discoveries over the past years. Again, adding some images to support this section would make it more interesting to read. Again, providing clickable links to the references would be better and make it easier for users to find the original references by clicking on the citation rather than scrolling down and manually looking for the citation in the references.
“Central Somatosensory Differentiation” is the best section so far. It is very well detailed with appropriate references and has an image to support the text. It even has clickable reference links which is good, as it makes it easier to find the references. It would be good to add a little bit more information to describe the image. And perhaps add a few more images to support this section.
Overall, you only have one image on your entire page. It would be good if you add some more images to support your text.

Current Research section needs more articles about current research. One article doesn’t seem sufficient. It is good that your image from the article has the appropriate reference.
Glossary section needs more words and definitions, there is not enough so far.
Some of the external links needs to be fixed. You need to change the format of the links and explain where the links would take you or what those web pages are about.

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Group 2- Somatosensory

-Great introduction. Really puts the project in context and justifies the importance of your research. Citations need to be formatted like the rest of the page

-History of discoveries-very poor syntax, word repetition and no paragraphs. What is Weber's full name? This is entitled "history of discoveries" when it is actually just a very brief, nonspecific summary of "Weber". What about the other interesting discoveries from various scientists over decades?

-Adult Central Somatosensory systems- ascending in what? Position? Importance? Activity? Sensitivity? This needs a more informative opening sentence.

-Trigeminal system and Development of the Primary Somatosensory Cortex- are well explained and ideas are presented in a logical, flowing manner. Great picture with a good description and referencing (impressed you drew it).

-"making connections between...." what do the stages mean? Why does it start at stage 23 instead of stage 1?

-touch/touch receptors is good but where are the references?

-pain and pressure sections also good but needs paragraphs and the formatting of citations is incorrect

-bullet points in pressure section need a brief sentence introducing their purpose. Papers listed at bottom of section should be correctly cited instead of having hyperlinks

-interesting info in temperature

-current research- maybe you could put the name of the paper and authors and explain how they conducted their study? That would help with understanding the nice picture

-Glossary is incomplete

-Needs more pictures

-minor grammatical and spelling errors throughout but overall very good and well sequenced.

==Search==

Hi, whoever wrote the history section, can you include some dates as to when the discoveries were made. I was thinking of putting that info into a table but we need the dates to do that. Thank you. --[[User:Z3332863|Z3332863]] 14:50, 15 September 2012 (EST)

[http://www.ncbi.nlm.nih.gov/sites/gquery?term=golgi+tendon+organ+development search pubmed GTO development]

'''Development of Nociceptors, Thermoceptors,and Pruriceptors'''

Lopes C, Liu Z, Xu Y, Ma Q. '''Tlx3 and runx1 act in combination to coordinate the development of a cohort of nociceptors, thermoceptors, and pruriceptors.''' J Neurosci. 2012 Jul 11;32(28):9706-15. <pubmed>22787056</pubmed>

'''Review for general Somatosensory development''' - just for background knowledge:

<pubmed>7812142</pubmed>
--[[User:Z3332863|Z3332863]] 14:53, 23 August 2012 (EST)

'''Central sensory Neuron development:'''

<pubmed>2918087</pubmed>
--[[User:Z3332863|Z3332863]] 14:53, 23 August 2012 (EST)

'''Article on Pain Development:'''

<pubmed>16446141</pubmed>

--[[User:Z3332863|Z3332863]] 10:05, 22 August 2012 (EST)

I think it would be cool to do an organ, but i'll be just as happy to do one of the senses. Does anyone have a specific organ they were thinking of?

My preference was '''Sensory''', but if we get organ that's fine also. If we did do organ I still want to look into some of the topics before I give my opinion, depending on the research and information behind it. If we got sensory, sight could be cool? - ==[[User:Z3330539|Z3330539]] 08:26, 10 August 2012 (EST)==

I'd prefer '''Sensory'''.

I agree; if we got Sensory, I would be happy to do '''Sight'''. But if we got Organ, I want to do the Heart but I'd be just as as happy to do another organ if anyone's keen.
--[[User:Z3332863|Z3332863]] 09:14, 10 August 2012 (EST)

Hi all,

I started with; and have mainly been looking into development relating to "Touch" and the receptors involved and time at which this occurs. I am happy to keep going or do research on the other categories as well? I will share what I found when we meet next. --[[User:Z3330539|Z3330539]] 22:02, 20 August 2012 (EST)--

Talk:2012 Group Project 1

2012-09-25T23:57:35Z

Z3330986: /* Group evaluations */

{{2012GroupDiscussion}}

--[[User:Z8600021|Mark Hill]] 09:58, 18 September 2012 (EST) This is a recent review on vision. http://jcb.rupress.org/content/190/6/953.full JCB content allows reuse.

*Introduction

*Research history?

*Developmental time line?

*Current research

*Useful links

*Glossary

*Image gallery summary

*References

==Group evaluations==

Use of historic images was good. This is a main point of difference between this project and the rest. They are however not very well integrated into the project page, they feel as if they have simply been pasted there for the sake of inclusion. Perhaps an explanation of their significance could be included as well as how these drawings have lead to more refined understandings of specific structures. The Research History section is also quite interesting although it is very brief and could be improved if it were presented in a more visually appealing manner such as in a colour table.

The development structure and function section is excellent. The text is easy to follow and the student drawn images demonstrate a clear understanding of the processes as well as giving the reader the opportunity to better visualise the different stages of development. Another image which could be included would perhaps be a histological picture (as opposed to a diagram) of the different cell layers of the retina ie. The photoreceptor layer, inner nuclear layer etc. The current research section needs further refinement. I see no reason to simply list some current research articles except for point of reference. What needs to be done is explain how current research has changed or challenged traditional views/concepts. A brief summary of each article listed in this section is also warranted.

All images and relevant ideas appear to be appropriately cited and referenced. Image formatting on the whole is quite good although I think those included in the introduction need to be altered as they skew the text, making the section look awkward and a bit difficult to read.

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The photo at the top of your page is a great choice and makes the site that much more appealing. The only suggestion I would have here is to potentially minimise the photo as it makes the contents section to the left of it hard to read. Your introduction is clear and concise and gives a good description of the eye. A slight adjustment I would make is perhaps to make it slightly longer giving a brief discussion about what is to be discussed on this page. Included in your introduction you have the anatomy of the eye. Firstly, would it be appropriate to include the histology as well, as it appears further down the page you discuss the cells, so perhaps if you gave a brief histological overview that could make the sections below easier for the reader to comprehend. I would probably add to that that if you were to include histology, to put the anatomy and histology into a new section just so it doesn’t clutter the introduction.

Your history, although I’m aware it ins’t finished, would read better if it were in a table and would also bring some more colour to the page. I’m assuming this will come when you finish this section, but it would be wise to include updated examples as well in order to show an adequate progression of the history.

The development section appears to be very thorough which is fantastic. It is rather clear that you have put a lot of research and time into this section. The introduction you have there is well written and again concise which is great. Additionally I like your use of photos just below it to further your explanation and also to break up the text. In regards to your photos, I would suggest perhaps a better description of them and to make sure you include where you got the photo from. If there were an explanation of the photo in simplistic terms, then I think the photos would be really beneficial.

The optic nerve section is well written but it appears to lack references?? In the first 3 paragraphs there are only 2 references. I would probably suggest that this information is backed up by additional sources as well. Also, with your hand drawn pictures (which are good), I would suggest an explanation on them when you open the picture up in another window. Your paragraph describing the 2 pictures, I would probably recommend that it become sintegrated within the text i.e. when you are talking about that part of it then include it there. I just think it would make it flow better that way – like you have done with figure 3.

The retina is good and well set out with pictures. However I noticed that you have used the exact references as before (3, 4)?? It would be really advisable to include many more references than what is listed. The same applies to the images as I said above, but good integration!

The ciliary body appears to be well researched and referenced. From the iris down there appears to be a lack of new references and also looks rather bland - so here I would suggest including additional photos from journal articles you have used. Also, it seems rather brief, I’m wondering whether there is more information about the embryological processes that could be included?

The current research is a good start, but there isn’t much of an explanation of the photo that is included and brief discussion of the research should probably be included. Are there additional research projects to include as well?

Finally, your references ar good but short. The fisrt 2 need to be put in the appropriate format. I would definitely suggest including many more references in order to make your information listed more valid.

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Good introduction, introduces the main components of the eye that will assumedly be focused on when talking about development. More information is needed in the history section however and the images used also need copyright permission.

Wording is simple and understandable, it’s also good to see that you guys have a glossary up so to make it easier to comprehend what is being read. However you need more information under current research. Also you should focus on the other components of the eye other than the Optic nerve and the Retina and add more pictures or diagrams to illustrate what it is you’re explaining.

You should also try using some dot points because reading long paragraphs could get tiring and allow the person to lose focus.

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Vision

Good descriptions of individual features of the eye. But seeing how the current task is the embryological development of the eye, it seems to be the smallest section of your wiki. Possibly a flow chart would be best to demonstrate the text you have in this section. Additionally, the information presented isn’t anything new or hasn’t been learnt in intro anatomy and could go further, as your current research section is still unfinished. Needs more current journal information

The text however in all of the sections is too dense and I feel my concentration waning when reading it. And although you have already an overall picture depicting the eye and it’s anatomical features, maybe for each section highlight the area that is being referred too. The timeline is unfinished and too wordy, needs to be more succinct.

The section of development of the optic nerve was really good, but again needs images to reinforce the text. Glossary and references are good, but need to be expanded. And a timeline of development would be useful.

Summary: text overwhelms the images and isn’t balanced.

Good luck with the rest ☺

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Overall, the key points relating to Vision and it’s development are being addressed at this stage by the page. There are some interesting descriptions that are easy to follow. However, in it’s entirety, the descriptions has to be sieved through in order to extract specific information. For example, the functions of each structure has been included in the development of each structure. While this provides a nice way for information to flow, it can be better received if function was separated from development and put under a separate sub-heading before development.

The history section, being in it’s early stages is off to a good start including some important contributions that date back to ancient times, which I find amazing. However, I would suggest, placing this information in the form of a table because full sentences are not necessary to achieve an understanding. It would also be important to include the specific advancements achieved from each moment, with relation to the eye. For example, what contribution did Aristotle’s dissection of the embryo, make to our understanding of the eye and it’s development? Does the age of the embryo tell us something?

Heading suggestions for the history:

1.TIME/PERIOD

2. HISTORIAN/SCIENTIST

3. EVENT

4. CONTRIBUTION TO OUR UNDERSTANDING OF THE EYE.

Moreover, the inclusion of the historic images are unique to the other groups and hence will spark an interest in readers. In saying this, the use of descriptions and appropriate titles will aid the readers in appreciating them from a contextual point of view.

Additionally, the scattered placement of images on the page makes it difficult to follow certain sections and properly use the images to aid my understanding. I suggest revising the method used and possibly having clear distinctions between images belonging to different sections. I.e. Some run over two sections.

I like how each component of the eye’s development is described separately giving us time to appreciated each one individually. However, the timeline of development is also important and sometimes, two components are dependent on each other for growth and development. This maybe something to consider when editing this section, so that an understanding that the entire process of growth and development overlaps amongst structures. A video might suffice here in place of text. Also, the importance of genes in patterning is not clear.

Current research section needs to built upon, maybe with some simple descriptions of the types of research taking place, their potential applications and limitations as well as the use of images that might help explain the conclusions of the project.
Finally, the glossary needs to be expanded upon but so far the definitions are nice and simple for anyone to understand.

Good luck!

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The huge picture of the eyes at the beginning of the page is perhaps necessaries. The title of the page "vision" introduces readers to the topic pretty thoroughly and comprehensively. A poorly formatted and redundant image is just an eye sore.
An explanation of the images under research history would be fantastic. At the moment it is hard for someone who does not know anything about the eye (myself) to use the images at all.
There is abundant information on the retina and optic nerve, with accompanying hand drawn diagrams, which is great.
The current research section seems underdone, seems to be more a link for me to go find the research myself. A little explanation of some of the current research would make it a more complete page.
Glossary and references well done and helpful.

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Great eye image at the start to capture attention. It's nice to see that it has the correct referencing and copyright.

The introduction is very clear and simple to read. Overall the written content is easy to understand and provides sufficient detail to cover the developmental stages of the eye and associated structures like the optic nerve and lacrimal glands.

The images throughout the project were very useful because they complement the text nicely. The student drawn diagrams made the optic vesicle formation easier to understand. However, I think the labels are a bit small - you can really only read them if you click on them and see the larger version. If you can put some labels on the orientation (such as the ventral side, posterior side, etc), that would be great too. Can you also put a reference as to where you got the information to draw these images from?

The images you got from the 'Atlas of development of man volume 2', can you put the copyright up? Not many textbooks allow using their images but if it is allowed for this book, you should definitely include the copyright there.

Sections that seemed incomplete are history and current research. with the current research information you uploaded, can you add a bit more text just to summarize what the study found out? There's a picture there with some description but it would be good if you can put into dot points what the significant findings are.

It would also be good if you can write something on the visual cortex of the brain. I think it links in with the section on Optic nerve. Maybe mention some of the genes related to the various stages of eye development. It doesn't have to be a lot of detail - just suggest what stage of development the genes are responsible for.

It would be good if you used more research papers instead of using the textbooks. If you are using the textbooks, it's good to track down the references the textbook used. This means you can put the relevant research papers as reference instead.

--[[User:Z3332863|Z3332863]] 16:08, 23 September 2012 (EST)

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- the opening is very catchy with the diagram

- good brief introduction although it might help to give a brief description of the different parts.

- Since you have no other tables maybe put the history section in the table so it breaks up the text.

- It might be better to make the images a little bigger so we can see the labels. Also with the images for ‘formation of primary optic vesicles’ you might want to fix the way it’s laid out on the page --- may be put it in a table with a description of what each labelled part contributes to. Also there is no description bellow the pictures either. All the pictures in the development area looks very clustered so break it up with text.

-Large section of the optic nerve development ad retina development seems to have no references. But a lot of good detail is present which shows that you have researched. Although try to use articles rather than books.

- The student drawn images have tiny labels so fix that up maybe and also add copyright information.

- Fig 4 and 5’s formatting should be fixed so they are either side to side or broken up by text. Same goes with fig 6 and 7 – needs copyright info.

- In the current research section a detail of what the research is about and how it is helpful can be given.

- Try using less websites and more journal articles.

- Sections of ciliary body, iris and lens development could use some more detail. The section on iris has the development time in months…it will be beneficial if you kept it in weeks to be consistent with the rest of the parts. The section on lens, aqueous chamber and cornea doesn’t have any development time associated with it which might be useful too.

- I’m aware that you cant do abnormal section in detail but you can still mention some abnormalities in a section without going into heavy detail.

Overall it is a good page but formatting of the pictures and their placement has to be fixed. Some more text should be added to the development section of iris, lens, eyelids etc.

--[[User:Z3333794|Z3333794]] 09:18, 23 September 2012 (EST)

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Firstly, the picture at the top immediately shows us the topic you are discussing: vision. This is good, but you might want to decrease the size slightly by stating the number of pixels in your file description. Your introduction includes the anatomy of the eye, which you should probably put under a separate heading. Expand the introduction a little and tell us what you will be presenting on your site.

The history is quite short – aim for more significant dates and discoveries and try to put them in an organised table. Within your history section you have images relating to development of the optic vesicle and lens. It seems like these should be incorporated in your next section on development. Good images though, but this time increase the size so the reader doesn’t have to open every single one of them to read the labels.

It seems like most work has gone into the section of development, which is good because we are focussing on the development of vision! The content relates really well and shows research has been done. There are a few sentences that strongly suggest they have been researched, however they are not references. This is in particular for the optic nerve and retina sections. Again, make sure the labels on the images can be read without having to open the file. You may also want to put the images together (optic nerve section) so the reader can easily see the changes happening during development. It is really good that you refer to the images within your text. The second half of your development section could do with a few images to complement the text. I personally think you should expand upon the lens development, because this is an important structure of the eye. What happens after migration into the embryo? If you find some related molecular information, eg. essential transcription factors, you could provide a brief explanation of these too and the role they play in vision development.

You started on your current research and a few references are present, as well as an image. I do not know what this image is and there is pretty much no text explaining any research that is currently undertaken. Please expand upon this!
The links should probably be listed under the heading ‘external links’ and as you expand upon certain sections, please keep adding to the glossary. For instance, I could not find the term ‘neuroblastic layer’ in the glossary (from the retina section).

With all of your images: please provide a title, description, source, copyright information, student image template. Some of your references will also need to be changed to avoid errors, citation of webpages and doubling-up of references. See the ‘editing basics’ on the embryology website.

Hope this helps!
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In regards to the information presented (outcomes 1 and 9), as the project is still in progress it is understandable that some areas are incomplete. There is so far good, concise information on the structure of the development of the eye and the structures involved in vision. It would be useful to include information on the genetic factors involved in vision development as well as have a section explaining the processes involved with vision. Also, for the Current Research section (outcome 5), it would be better to explain the aims and findings of the research papers cited rather than just referencing the papers and images without describing their significance to research progress. In terms of peer teaching (outcome 4), the page contains a good balance between technical terms and simple language for understanding on the development of structures for vision; additionally, the inclusion Glossary helps to clarify any technical terms.

The most striking part of the layout (outcome 2) is the use of images to demonstrate the development of structures involved in vision. This is great because it makes the page interesting and provides a visual understanding on the development of the eye. However, at times the images could be better placed: for example, in the introduction the pictures appear stacked on top of one another. Additionally, the images in the introduction show similar structures, so perhaps select only one to better aid the flow and appearance of the page. Throughout the page, the images utilised could be provided with more description and linked to the text in order to improve flow and enhance written explanation. Perhaps some information, such as the timeline, could be sorted into a table to improve the layout.

In regards to outcome 3, some of the information provided (e.g. in the section on Development) is not referenced. Additionally, some of the references in the Reference list need to be formatted correctly with author, date, title of the page, publisher (if required) and any other necessary information. It would be useful to follow the style of the automatic default referencing.

Hope the feedback helps and all the best with your project!

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Group Assessment Criteria:
# ''The key points relating to the topic that your group was allocated are clearly described'' The introduction explains why the eye is important and lists the anatomical structures, however there is no indication that this project page is about the development of the eye!
# ''The choice of content, headings and sub-headings, diagrams, tables, graphs show a good understanding of the topic area''. The project predominantly focuses on the development of the eye, and goes into detail the development of each individual structure. There are also a lot of student-drawn images and diagrams of developmental stages which shows a good understanding of the topic area.
# ''Content is correctly cited and referenced''. There is no copyright notices for any of the images and they all lack explanations.
# ''The wiki has an element of teaching at a peer level using the student’s own innovative diagrams, tables or figures and/or using interesting examples or explanations''. The text is easy to understand and there are many student-drawn diagrams, which makes the content more interesting to read.
# ''Evidence of significant research relating to basic and applied sciences that goes beyond the formal teaching activities''. I would say the information provided satisfies the aims of the project, however the research does not go ‘beyond the formal teaching activities’ as it lacks additional information such as abnormalities, normal functioning etc.
# ''Relates the topics and content of the Wiki entry to learning aims of embryology.'' The contents and topics are strongly related to the learning aims of embryology.
# ''The content of the wiki should demonstrate to the reader that your group has researched adequately on this topic and covered the key areas necessary to inform your peers in their learning.'' All the content provided is well researched and relevant to the aims of the project. They key areas are well described.

Additional points:
* I feel that this page would benefit from a timeline or ‘weekly development’ table that briefly describes what structures are developed in each week. This would provide a good summary of the content as well as allow reader to be able to understand how the development of each structure relates to each other.
* Good referencing of images throughout project page – relating images to content
* Less paragraphs, more tables, bullet points, emphasize certain important points
* History & research sections look incomplete.

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Vision development review:

The key points are Cleary described and Topics have been divided in an efficient way allowing maximum information and an extensive insight into each of these segments, although at this stage there is not enough detail for each.
There is a substantial amount of visual stimulus although the quality of these stimuli is questionable. For example the images under the heading “research history” lack proper sized labelling, an individual must click on the each image in order to appreciate it. The initial image needs to decrease in size dramatically as is overwhelming and takes away from the product
Proper citation is evident however; there is a minority of untidy citations along with no copy write information for a certain image. Significant, deep research is not evident, I believe more research is required; there is a respectable attempt to relate content to learning aims of embryology. Information in the history section is insufficient and perhaps needs to be expanded upon.
To improve more information on each topic is required, review of visual displays (mainly balancing images between sections some have plenty where as other lack) and copy write information is essential

--[[User:Z3330795|Z3330795]] 10:20, 24 September 2012 (EST)
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The layout of the page is relatively good. If anything it appears little too image heavy at the moment. On the note of images, the referencing is good but don't forget to include the student template note with each image. The inclusion of some student drawn images in great to see but it might be an idea to make the labels larger as they are hard to read. The use of subheadings is great, a really logically well set out page. The references need a bit of work, some are spread sporadically throughout the page and some in the references section just list the URL along with the error on reference number 13.

The introductory is brief but alright. However the first two images are largely similar, not sure why both need to be included. Perhaps if possible it would be nice to link each of the main anatomical bullet points you have listed in your introduction to their associated developmental paragraph further down the page.

The History of development is coming along nicely but perhaps would be easier to read if it was in the format of a table. Also the Atlas of the Development of Man needs to be properly referenced with the author in the reference section. It would be nice to have some information relating to the pictures uploaded in this section.

The section on Development is well done and it is interesting to look at the individual development of each structure. It might be an idea to include some more references to when each structural development occurs. Current Research really needs some more content. The glossary is a nice addition and helpful.
Hope this helps

-----------------------------
The top image of the eyes is a great idea to introduce an audience to your topic. The copyright of the image is there along with the reference. However, the hand drawn image do not have a reference as to where you located the information for the diagram. The images further down the page which are referenced to a textbook had no copyright associated with it. It is important to make sure that the textbook is not protected by copyright laws before placing those images in your page. Referencing and copyright needs to be included in every image on the page, many of your images don't have the necessary information.

The information is easy to understand, however it is difficult to locate. Things seems to be out of place. Try not to include images on both side of the page, it is highly distracting as they alternate far too often. I also noticed that development and function were both under one heading. This made things a little confusing as the information between the two topics were shared in the same paragraph.

What I found to stand out were the historic images. These are a great addition to the page. Having said that, they're often difficult to understand and therefore explaining the images would be great. The history, current research and glossary sections all seem to be incomplete, these need to be worked on.

Something that i found to be really well explained was the developmental stages of the eye and associated structures. This is very important as the topic is about the development. Although the information for this section seems to be great, there seems to be a lack of references, it is important to cite where you derived the information from.

Overall the page seems to have the right information, however, just remember to include the right references, make your diagrams and labels more visible and try to organise your information into tables or dot points to make it easier to follow.

Hope this information helps

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There is a good balance of images and text throughout the page. Prior to final assessment the page outline and formatting of image and text positioning is required. The first image at the top the page, requires correct referencing and acknowledgement that it has been uploaded as part of a student assignment. This is also required for the image titled “Eyediagramcolour1”.

Since the previous lab, held in week 9, it is positive to see that the group has altered some of the uploaded image information, with particular reference to the self-drawn/uploaded images.

The area of the page which shows that there is a “useful links” heading and an external link within the current research section, should be placed or moved into the external links section at the bottom of the page with the appropriate information that Dr. Hill has required for placing external links on a page. Also, the references within the ‘current research’ section may also need to be apart of the reference list.

I found this page visually appealing and I liked that this group have included an image gallery section. The use of the external links were appropriate to the topic and that the extent of the glossary for now is good, however, by the final evaluation would potentially need to be larger. Finally found that the headings for each segment of the broader topic were well positioned and relevant.

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'''Vision'''

Overall the detail within Group 1's page is very informative and very well set out, having each individual part of the eye named with information about the development of that certain feature is great. The information about the iris, cornea, choroid and sclera, eyelids and lacrimal glands were undeveloped compared to that of the retina and optic nerve. Even though the retina and optic nerve are the sensory receptors, the other components of the eye should have an equal amount of information about the development because without these parts the sensory part would not function at its best.

I would recommend having developmental pictures that you have placed at the beginning of the page places around the block of writing in the iris, lens, and chamber area just to break up the text and to show the development of each part in stages. The History section, as they stated has more to come, and I hope there is more to come for the current research as well as both sections need more information.
I feel that the images, while being hand drawn, were not sufficient enough to communicate the full detail of the developmental process and there were not enough references to validate the statements that were made throughout the page.
Overall however it was a very well written project with a well thought out progression from introduction to finish.

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The introduction is good, I like the use of images to help describe your topic. The images you have for your page are great. They complement the information you have on your page however the historical images at the top of the page feel like they are added because they are images, they should have a small description and be numbered if you like to show the order they go in. As is stands at the moment I found them to be confusion and just a space filler.

Under the current research heading, I think you guys would benefit from giving a brief overview of what the research is not just listing the articles.

If possible you should add a part about the first person/s to discover the mechanisms of eye development. You should also add a small part about the genetic parts which cause these mechanisms.
--[[User:Z3220343|Z3220343]] 21:28, 25 September 2012 (EST)

== Group discussion ==

Have you guys looked at some sources about the development of vision in embryos?
Do you have any idea how you want to divide up the topics we can work on?
--[[User:Z3370664|Z3370664]] 13:31, 21 August 2012 (EST)

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Hey everyone, I haven't looked at anything yet, sorry! Hopefully end of this week/start of next I'll start adding things. Ben --[[User:Z3373894|Z3373894]] 19:33, 21 August 2012 (EST)

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Heya. Thinking that we should do a time line rather than dividing up the different structures of the eye. Em --[[User:Z3254758|Z3254758]] 10:40, 22 August 2012 (EST)

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I looked through all the embryology textbooks I have (the two prescribed texts, as well as another book) and they all divide up the eyes into different parts and talks about how each of the parts develop, rather than a timeline. So i was thinking, maybe we could focus more on describing how each of the different parts of the eye develop, and then we could do a timelime briefly at the end? (By the way, you're not supposed to mention your name) --[[User:Z3370664|Z3370664]] 10:21, 29 August 2012 (EST)

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Sounds good. I have put a few suggestions for the different parts of the eye on the page. We need code-names if you don't want to put your name so that we know who is saying what.
Please don't put any information on the actual page without referencing it.--[[User:Z3254758|Z3254758]] 10:45, 29 August 2012 (EST)

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We also can't use content from Dr Hill's pages. The photos that are on our page are great, but we will have to replace them. We also desperately need to divide the sections between us. Maybe 2 people do 5 eye structures each, one person does intro and history, and another does current research and useful links? --[[User:Z3254758|Z3254758]] 11:45, 29 August 2012 (EST)

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The textbooks are going to be really useful, I'd say divide it up the way the textbook does it. Sorry guys, didn't realise we can't use Mark's stuff. Will look for similar images later -.- --[[User:Z3373894|Z3373894]] 11:51, 29 August 2012 (EST)

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Also I'm happy to do 5 eye structures :) I think. --[[User:Z3373894|Z3373894]] 11:56, 29 August 2012 (EST)

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Okay guys, I'm doing retina and optic nerve, lens, eyelids, choroid and sclera. Em (z3254758) is doing the other structures (we can reassign if either of us find a structure that is excessively complicated). That leaves intro/history and current research/useful links. '''Also!!!''' I have to do a marine science camp in the mid sem break and so won't be available to make contributions. Sorry but I'll keep adding as soon as uni goes back. --[[User:Z3373894|Z3373894]] 12:13, 29 August 2012 (EST)

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Awesome, no worries. Thanks for your contribution so far, let me know if we need to redistribute. Enjoy your camp! --[[User:Z3254758|Z3254758]] 16:08, 29 August 2012 (EST)

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Hey guys I'm really sorry for the late notice but I've dropped this Embryology course. Tried logging on a few days ago to let you know what was going on but the server wouldn't connect. So sorry to stuff you all around. Goodluck with everything. Emma --[[User:Z3330686|Z3330686]] 10:55, 5 September 2012 (EST)

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So does this mean we only have 3 people in our group now?

Anyway, I'm sorry i haven't contributed yet. I had been looking up articles and reading them to help you with the structures, but haven't written up notes yet, as I have so many other assignments to do that are all due soon. I am happy to do intro/history and current research/useful links. And after i do those parts, I can help you guys with the structures if there are any structures you're stuck with. I can help look for images too. I'll also do a brief timeline/overview of eye development after you guys finish the structures. I'll post up the links to the articles I found that you might find useful for the structures. --[[User:Z3370664|Z3370664]] 12:22, 10 September 2012 (EST)

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Oh my goodness the more I research the more confused I get! I keep finding conflicting information- hence why some things are in capitals and italics and why I haven't put references for everything. Am hoping you guys can shed some light? For the iris I had one resource that said two completely opposite things about what it develops from :S :S :S

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Yeah I know, I've had similar problems of conflicting sources :( I'm mostly relying on the online textbooks because surely they can't be wrong? And all the papers have a large emphasis on the genetics and it's hard to find a simple anatomical description. We can come back later and fix anything that's unresolved. --[[User:Z3373894|Z3373894]] 14:35, 17 September 2012 (EST)

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P.S. nice eye collage at the top whoever posted it. Adds a nice human touch. It's really cool to look at! :)

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yay I'm glad you like it! :)
This is the problem, I was confused about the conflicting statements so I went to a textbook and that was what said the two different things... in the specific section it said one thing and then in the summary it said the opposite o_O trying a few other textbooks at the moment. Ya am very sick of reading about genetics.--[[User:Z3254758|Z3254758]] 21:49, 17 September 2012 (EST)

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Hey i found a good article which i think you might find useful. It also has nice images. I want to email them and ask permission to use their images in our project.

To read the article, Log into the UNSW library and search 'Eye development' by Jochen Graw

Current Topics in Developmental Biology, 2010, Vol.90, pp.343-386

--[[User:Z3370664|Z3370664]] 23:49, 17 September 2012 (EST)

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Well peer review is tomorrow and the page is still somewhat lacking haha... It would be good to get something under the headings "research history" and "current research" even if it's only a few sentences so the space isn't completely blank. I'll try and add a few more things to my sections tomorrow morning. I had a quick look at the Jochen Graw article and it has good summaries of genetic stuff as well. Once I get all the anatomical stuff down on my sections I'll come back and add genetic stuff at the end if I get time. --[[User:Z3373894|Z3373894]] 17:16, 18 September 2012 (EST)

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Hey guys, I went through the page and fixed some formatting issues with the images. Also went through my images and added descriptions, copyright and the "student template" thing - don't forget to do that to all the images you upload. I also took some of the advice in the comments and enlarged my labels and added an orientation to my images. Don't forget that according to the course timetable that this project is due at the end of the lab next week!!! That's '''Wednesday 3rd October.''' So keep adding stuff!!! --[[User:Z3373894|Z3373894]] 17:15, 25 September 2012 (EST)

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Okay I also just went through and fixed up the references we have so far, so instead of having the same reference come up multiple times in the reference list it just comes up once. Here's the help page that tells you how to do it: http://embryology.med.unsw.edu.au/embryology/index.php?title=Help:Reference_Tutorial#Multiple_Instances_on_Page

I think we should try and get content from all of the potential papers you guys posted below on this page so we get a nice, well rounded reference list. We've already referenced the textbooks several times (I am mostly guilty of this - sorry), so let's try and reference the same info in papers instead. Also try and get the reference info right the first time - it takes ages to go back and do it!!! --[[User:Z3373894|Z3373894]] 18:16, 25 September 2012 (EST)

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==Potential Resources==

<pubmed>16959249</pubmed>
<pubmed>11687490</pubmed>
<pubmed>22219630</pubmed>
<pubmed>19449303</pubmed>
<pubmed>11069887</pubmed>
<pubmed>12223402</pubmed>

--[[User:Z3254758|Z3254758]] 17:58, 4 September 2012 (EST)

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Lhx2 links the intrinsic and extrinsic factors that control optic cup formation:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2778739/?tool=pmcentrez

Innervation of the Mouse Cornea during Development:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3053279/?tool=pmcentrez

Fibromodulin Regulates Collagen Fibrillogenesis During Peripheral Corneal Development:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2965449/?tool=pmcentrez

Development of extraocular muscles require early signals from periocular neural crest and the developing eye:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3248700/?tool=pmcentrez

Eye Morphogenesis and Patterning of the Optic Vesicle:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2958684/?tool=pmcentrez

Targeted deletion of Dicer disrupts lens morphogenesis, corneal epithelium stratification, and whole eye development:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2787093/?tool=pmcentrez

Anterior eye development and ocular mesenchyme:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2094210/?tool=pmcentrez

--[[User:Z3370664|Z3370664]] 12:31, 10 September 2012 (EST)

User:Z3330986

2012-09-25T23:54:10Z

Z3330986: /* Lab 7 */

==Lab Attendance==
Lab 1
--[[User:Z3330986|Z3330986]] 11:49, 25 July 2012 (EST)

Lab 2
--[[User:Z3330986|Z3330986]] 10:25, 1 August 2012 (EST)

Lab 3
--[[User:Z3330986|Z3330986]] 10:33, 8 August 2012 (EST)

Lab 4
--[[User:Z3330986|Z3330986]] 10:21, 15 August 2012 (EST)

Lab 5
--[[User:Z3330986|Z3330986]] 10:27, 22 August 2012 (EST)

Lab 6
--[[User:Z3330986|Z3330986]] 11:55, 29 August 2012 (EST)

Lab 7
--[[User:Z3330986|Z3330986]] 10:54, 12 September 2012 (EST)

Lab 8
--[[User:Z3330986|Z3330986]] 10:31, 19 September 2012 (EST)

==Individual Assessment==
===Lab 1===

1) As with many medical terms, ''in vitro'' is derived from Latin, translating to "in glass." It is so named, as early experiments involving tissue cultures outside of the specimen (as opposed to ''in vivo'', inside the body) were undertaken in glass containers. In Vitro Fertilization was developed by Robert G. Edwards. He was awarded the Nobel prize in 2010 in the field of medicine and physiology for his work. A link to the Nobel prize web page can be found here:[[http://www.nobelprize.org]]

2) '''Sperm counts and sperm sex ratio in male infertility patients'''[[http://www.ncbi.nlm.nih.gov.wwwproxy0.library.unsw.edu.au/pubmed/22842703]]

In this study, the sex chromosomes and sperm count of infertile men were analysed in order to determine whether infertility plays a role in the determination offspring gender. Infertility is a fairly arbitrary categorization though for the purposes for this experiment, it was taken to mean couples who had greater than or equal to two recurrent pregnancy losses or two failed IVF treatments. The subsequent results found that in men with a low sperm concentration, semen volume and total motile sperm count, there was a significantly lower proprortion of the Y-bearing sperm. Thus there is a direct link between spermatogenesis and sex ratio.

The precise mechanisms for a diminished Y-bearing proportion of sperm is unclear. It is suggested that perhaps societal stresses or individual wants and needs may play a role in the genetic makeup of sperm. Biologically, it is reasoned that an infertile man will produce less male heirs so as to minimise the chance that his offspring may encounter the same problems.

===Lab 2===

[[Image:Mouse oocytes in vitro.png|thumb|Mouse oocytes in vitro]]

In order for successful implantation to occur, estrogen controlled proliferation of the uterine epithelium must be attenuated by the hormone progesterone. Previously the mechanisms of attenuation were not well understood however recent study has shown the helix-loop-helix protein, Hand2, plays an integral role in
suppressing estrogen-driven growth of uterine epithelium. It does this by stopping the induction of Fibroblast growth factors (FGF) which are responsible for maintaining estrogen mediated growth of the epithelium. [1]

From a clinical perspective it may also direct research to improve treatments which target over-proliferative disorders such as endometriosis and endometrial cancer. Particularly endometriosis, which currently resists progesterone targeted medications.

'''Reference'''

1. The Antiproliferative Action of Progesterone in Uterine Epithelium Is Mediated by Hand2
Quanxi Li, Athilakshmi Kannan, Francesco J. DeMayo, John P. Lydon, Paul S. Cooke, Hiroyuki Yamagishi, Deepak Srivastava, Milan K. Bagchi, and Indrani C. Bagchi
Science 18 February 2011: 331 (6019), 912-916. [DOI:10.1126/science.1197454]

===Lab 3===

1) Gestational age refers to the age of the foetus/embryo beginning at the first day of the mother's last menstrual cycle. In contrast the post-fertilisation age, as its name infers, begins at the time of fertilisation of the oocyte.

2) Somites mainly generate: Skeletal muscle and dermis (from the dermomyotome) as well as intervertebral discs and vertebral bodies (from the sclerotome)

'''Histology'''

*Skeletal muscle - Contains densely packed fibers called myofibrils. These are cylindrical, long and multinucleated fibres with nuclei residing peripherally. Each myofibril is composed of the proteins actin and myosin (referred to collectively as myofilaments). Skeletal muscle can be divided into either red fibres or white fibres:

::*Red fibers are named due to the presence of myoglobin, an oxygen transporting protein, analagous to haemoglobin in the blood. They contain many mitochondria and are responsible for slow twitch contractile movements.

::*White fibers are larger with less myoglobin and mitochondria. These represent fast twitch fibers

*Dermis - Bilaminar structure composed of Papillary layer and Reticular layer.

::* Papillary layer - Superficial layer interdigitating with the dermis. Composed of loose connective tissue with thin type III collagen fibers. Also contains macrophages, fibroblasts and mast cells along with capillary loops which function in thermoregulation.

::* Reticular layer - Deepest layer containing intermingling thick elastic fibers and collagen fibers.

*Intervertebral disc - made up of fibrocartilage. The matrix contains cartilage cells, enclosed within lacunae which align in pairs or short rows between bundles of type I collagen fibers.

===Lab 4===

There are two main types of invasive prenatal diagnostic techniques

* Amniocentesis - Amniotic fluid is taken and analysed between 14th and 18th week of pregnancy. It is used primarily to test for chromosomal defects such as Down Syndrome or fetal infections. It may be used to test for maternal hypertension (''preeclampsia'') by looking for protein biomarkers.

* Chorionic villi sampling - Cells from the chorionic villus are taken between 10th and 12th week gestational age. It is used to test for chromosomal abnormalities such as Down syndrome or cystic fibrosis.

2) '''Systemic administration of a novel human umbilical cord mesenchymal stem cells population accelerates the resolution of acute liver injury'''

Traditionally when liver hepatocytes are damaged during end-stage liver disease, the only option has been transplantation. New research conducted by Burra et al (2011) however has focused upon using human umbilical cord mesenchymal stem cells (UCMSCs) as a form of regenerative treatment. In this study, UCMSCs were induced to form hepatic cell types through the use of growth factors ''in vitro'', whilst ECM components derived from surgical specimens were used as a basis of support for these cells. These cells were then transplanted into carbon tetrachloride infected mouse livers which had undergone more than 40% necrosis of its total parenchymal tissue.

When UCMSCs were recruited within liver tissue, it was found that inflammation had been reduced through the regulation of pro-inflammatory cytokines and reduction of infiltrate. Furthermore there was a higher proportion of Kupffer cells (liver macrophages) identified through histological analysis compared to untreated liver tissue. This finding lends weight to the idea that UCMSCs accelerate liver cell recovery by attenuating the inflammation process.

Another therapeutic advantage of UCMSCs was the increase of catalase activity. The amount of catalase enzyme present in UCMSC treated liver tissue was markedly increased around Day 5, resulting in enhanced elimination of reactive oxygen species (ROS) which would otherwise cause oxidative damage to hepatocytes.

===Lab 7===
1a) A satellite cell, also referred to as a muscle stem cell, is a quiescent cell which functions to repair and or form new muscle fibres.

b) Activation of satellite cells occurs primarily during muscle injury. When a muscle fibre is damaged through physical injury, the satellite cells become mytotically active and fuse with the existing muscle fibres to repair the damaged tissue. Similarly in chronic diseases such as Duchenne’s muscular dystrophy, satellite cells are activated and differentiate into new myotubes in order to replace dying muscle fibres.

2) Damage to the motor nerve, classified as a motor neuron lesion, manifests in flaccid paralysis in the affected individual. This is a result of the loss of electrical signalling from the motor nuclei of the spinal cord to the muscle spindle. Consequently the individual presents with reduced muscle tone (hypotonia) and muscle wasting (atrophy). On a cellular level, muscle fibre size decreases whilst there is a fibre type shift from type I to type II fibres. This represents a down regulation of the slow myosin heavy chain (MHC) isoform and up regulation of fast MHC isoforms. [1]

'''References'''

1. Scelsi, R (2001). Skeletal Muscle Pathology after Spinal Cord Injury: Our 20 YearExperience and Results on Skeletal Muscle Changes in Paraplegics,Related to Functional Rehabilitation. Basic Appl Myol 11 (2): 75-85,

==Peer assessment==

===Vision===

Use of historic images was good. This is a main point of difference between this project and the rest. They are however not very well integrated into the project page, they feel as if they have simply been pasted there for the sake of inclusion. Perhaps an explanation of their significance could be included as well as how these drawings have lead to more refined understandings of specific structures. The Research History section is also quite interesting although it is very brief and could be improved if it were presented in a more visually appealing manner such as in a colour table.

The development structure and function section is excellent. The text is easy to follow and the student drawn images demonstrate a clear understanding of the processes as well as giving the reader the opportunity to better visualise the different stages of development. Another image which could be included would perhaps be a histological picture (as opposed to a diagram) of the different cell layers of the retina ie. The photoreceptor layer, inner nuclear layer etc.
The current research section needs further refinement. I see no reason to simply list some current research articles except for point of reference. What needs to be done is explain how current research has changed or challenged traditional views/concepts. A brief summary of each article listed in this section is also warranted.

All images and relevant ideas appear to be appropriately cited and referenced. Image formatting on the whole is quite good although I think those included in the introduction need to be altered as they skew the text, making the section look awkward and a bit difficult to read.

===Somatosensory===

The introduction is ok, there is an imbalance between text and pictures. Particularly there is a sentence which reads “The following picture shows the general organization of the somatosensory system” however there is no picture. Also in terms of sentence structure, there are four sentences in a row which begin with “the somatosensory system...” or “the system...” Try to alternate how different ideas are expressed as at the moment the paragraph reads as a disjunct of ideas.

As a whole the page’s visual appeal needs ameliorating. There is far too much text and only two pictures, one of which is very large and appears to be compensating for a lack of smaller relevant diagrams within the body of each section. Having said this, the neural development section was very well done. It was detailed without being verbose and showed it was well researched. The hand drawn diagram is excellent. The cell biology part was also very well written and well structured however again, it simply need some visuals to aid in some descriptions of molecular processes.
There appears not to be a continuous referencing style on the page. The introduction has in-text referencing whilst the rest of the page contains endnotes. A minor problem which could be fixed easily, though quite important nonetheless.

===Olfaction===

The project page was exceptional, there is a fine combination of text and images and the images are well integrated with the presented information. I particularly like the inclusion of a hand drawn histological section embedded within the table of historical findings. Perhaps this could also be done in the next table about the developmental timeline. As it stands, this table, while detailed in its wording may be difficult to understand as there are no diagrams to show the differentiation in visual terms, from week to week.

The clinical features, anatomy, and pathohophysiology were excellent. There is not much more to say. All of the diagrams were properly cited with correct copyright information. The CT scan was also interesting to look at.

One aspect that hasn’t been touched on is future research. The current research section was very detailed and explained the significance of each new finding however as is the nature of research, there are always gaps left in our understanding or further questions that need to be resolved as a result of new information. A brief section on this would give the project more depth as it would show a level of critique rather than simply the presentation of fact.

===Abnormal vision===

From the outset the page presents as well structured, particularly the introduction which provides the reader with a clear understanding of the purpose and content of the page. The following content is detailed and well researched with equal emphasis place upon each section. It appears that the page was contributed to equally by each member.

The image comparing the fundus between albinism and a normal eye is too small. The formatting is easily fixed by including the pixel size in the image insert directory. To find out how to do this refer to the wiki reference card we were given, or online.
One minor structuring problem comes from the “ocular manifestations” sections. When it says “Major ocular disorders can be split into two separate sections based on the way in which they originated,” please list the two separate classifications immediately in bullet form. i.e.
*Genetic
*Environmental

By the time the section about the environmental origins arises, I forgot what it was referring back to and thus I had to scroll back up to deduce it was the second part of the ocular manifestations heading. Apart from this there are no other major faults of the project. All images are cited and copyright information clearly recognisable.

===Hearing===

I liked the tone of the introduction, it was light hearted and enjoyable to read, especially the image of the dog in the beginning which I thought was great. It also instructed the reader about the content of the page, thereby having a good balance between being engaging and informative.

The development section is extremely detailed, which is good in terms of showing a breadth of research and understanding however this needs to be offset with a greater deal of visual information. The subsections detailing the middle and outer ear are in need of some images showing the pharyngeal arches and their morphological changes from week to week. It would also be nice to see either some hand drawn images or computer drawn diagrams included somewhere in the page just for some variation. Towards the end of the page in the Abnormal hearing and the technological sections it tends to become very text heavy and need some image content. For example a photo of a cochlear implant would be useful.

There is some variation in the referencing style in Technology section with references appearing at the end of the section. It would be better to incorporate these references into the text as endnotes as they appear in the other sections of the project. Furthermore some of the tables are incomplete and require the addition of images. The image column in the structural malformations of the ear is empty. I’m not sure if there was a formatting problem or otherwise, though this need to be rectified.

Overall the page is very well written with an appropriate style aimed at students of the same level or higher. The glossary is extensive as is the reference list, showing an obvious depth of research.

File:Taste map.png

2012-09-25T13:07:35Z

Z3330986:

==Information==
Student hand drawn image demonstrating the outdated concept of a 'tongue map' which suggests different taste qualities are region specific on the surface of the tongue

==Copyright==

I (z3330986) grant the public the non-exclusive right to copy, distribute, or display the Work under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/3.0/ and http://creativecommons.org/licenses/by-nc-sa/3.0/legalcode

2012 Group Project 3

2012-09-25T13:02:45Z

Z3330986: /* Taste Map */

=Taste Development=

==Gustatory System==

===Introduction===

[[Image:Taste qualities.gif|thumb|The five basic tastes]]

Taste or more appropriately gustation, is a fundamental survival tool in animals as it directs the consumption of essential nutrients. The five tastes that exist within the human gustatory system: salty, sweet, sour, bitter and umami, all signify basic physiological requirements. Salty tastes denote the presence of Na+, an important ion involved in the transportation and retention of water across cell membranes. Sweetness is the recognition of carbohydrates, essential for maintaining optimal brain function and providing the basis for energy production in muscle tissue via ATP hydrolysis. Similarly umami codes for the presence of L-amino acids, especially L-glutamate which is an integral component of protein synthesis.

These different modalities not only function to maintain the proper intake of nutrients within the body but also, by way of aversion, prohibit the consumption of undesired or poisonous materials. The bitter modality for example is generally regarded as displeasing to the human palate. It represents a high acid content which may be a result of foods which have become rotten or are inherently poisonous to the body.<ref name=PMID20696704><pubmed>20696704</pubmed></ref>

Research has historically limited itself to investigating the mechanisms of these five taste qualities though it must be noted many other modalities may exist. Of particular conjecture is the existence of fatty acid recognition. In the past the detection of fat in food has been attributed to somatosensory inputs <ref name=PMID20696704/> from the tongue, that is, the oily feel and texture of fat rather than its actual ‘taste’ allows the brain to encode for its presence. Further research is therefore required to elicit the precise mechanisms of fat detection.

===Cell Biology===

The five taste qualities are not all detected by the same type of receptor cell located within the taste bud. Like rods and cones in the eye which detect different wavelengths of light, there are specific types of receptors for different tastes. For example, sweet, umami and bitter are recognised by Type II G-protein coupled receptors, whereas sour is related to Type III presynaptic cells. The cell type involved in salty taste transduction is unknown however it is known that sodium ions can enter the receptor cell membrane via ion channel permeation.

====Type II receptors====

When a bitter, sweet or umami ligand binds to a type II G-coupled receptor, a cascade of chemical reactions causes the release of Ca2+ which in turn mediates exocystosis of ATP. The function of this ATP is threefold:

# Stimulates gustatory nerve afferents which project to gustatory nuclei in the spinal cord
# Excites Type III presynaptic nerve fibres to release serotonin.
# Has a positive feedback effect on type II receptor cells, increasing the level of ATP production.

The role of serotonin is believed to be in the form of lateral inhibition i.e. when a bitter quality is recognised, adjacent receptors for sweetness are deactivated and thus the two tastes may be clearly differentiated. It also has a negative feedback effect on receptor cells, inhibiting umami, bitter and sweet taste transduction.

==Taste Map==
[[Image:Taste map.png|thumb|left|250px|Obsolete idea of the tongue map]]
The idea of a tongue map has disseminated through society for many years. This concept purports that different areas of the tongue are specialised to detect either sweet, salty, sour and bitter tastes. Recent research however has completely nullified such claims and suggests instead that different forms of taste are recognised all over the tongue as well as via the palate. Thus the term ''taste map'' has come to take on a new meaning and that is, the precise areas of taste modalities processing in areas of cortex and its subsequent neural inputs.

===Neural Pathways===

'''First order neurons''' - From the receptors located in the taste buds, gustatory nerve afferents project to the ipsilateral rostral 1/3 of the nucleus tractus solitarius (NTS), located in the medulla. This rostral 1/3 is commonly referred to as the ''gustatory nucleus''.

The ''gustatory nucleus'' receives input from cranial nerves VII (''Facial n.''), IX (''Hypglossal n.''), and X (''Vagus n.'') via special visceral afferent (SVA) nerve fibres. A summary of their functions is as follows:

* ''Facial nerve n''. - carries taste information from the anterior 2/3 of the tongue.
* ''Hypoglossal n.'' - carries taste information from the posterior 1/3 of the tongue.
* ''Vagus n''. - carries taste information from the palate

'''Second order neurons''' - From the NTS second order neurons carry taste information to the Ventral posteromedial (VPM) nucleus in the thalamus.<ref name=PMID21885776/>

Copious scientific conjecture surrounds how each taste modality is transmitted to the brain. The ‘labelled-line’ hypothesis suggests that there are taste specific neurons which exclusively carry that taste modality to cortical areas. In analogous terms it can be viewed like the pipelines leading toward a house. Each pipeline carries its own utility, there is one for gas, another for water and finally for electricity with each terminating in slightly different areas of the house. In the same way, on the tongues there are different receptors for each taste which concurrently have individual nerve tracts leading to the primary gustatory cortex.

Contrapuntally there is electrophysiological evidence that single nerve afferents carry multiple modalities. These studies show one nerve afferent may have both a strong and a weak activation in response to a multiple taste stimuli.

===Cortical Areas===

[[Image:Primary gustatory cortex.png|thumb|Primary gustatory cortex]]

The location of the taste perception centres has been observed via functional magnetic resonance imaging (fMRI) studies. The primary taste cortex has been identified as being located in the anterior insula/frontal operculum (I/fO)<ref name=PMID22245354><pubmed>22245354</pubmed></ref>, with the secondary taste cortex in the caudolateral orbitofrontal cortex.<ref name=PMID21305668><pubmed>21305668</pubmed></ref> Within the insula there are further subdivisions related to each taste modality. Two photon calcium imaging research has outlined certain ’hot-spots’ of activation which are clearly delineated in relation to each taste. For example, the bitter modality is represented on the insula cortex approximately 1mm posterior to the middle cerebral artery whereas the sweet modality is represented 2.5mm rostrodorsal to the bitter field with no apparent overlap.<ref name=PMID21885776><pubmed>21885776</pubmed></ref> These findings lend weight to the idea that there is only one receptor for each taste quality.

It is interesting to note the relationship between taste and the reward centres of the brain. There is evidence of neural input to the ventral tegmental area (the origin of the mesolimbic dopaminergic reward pathway) and nucleus accumbens (involved in the conversion of motivation into physical action).<ref name=PMID21885776/> Neural connections such as this provide the foundations in explaining concepts such as flavour learning and preference. It may also give some insight into chronic problems such as food addiction and craving. As of yet however the gustatory neural network is not well understood and more research is required to elucidate the relationship between pleasure and taste sensation

==Timeline of Developmental Processes of the Gustatory System==

{| cellpadding=5 style="border:1px solid #BBB"
|- bgcolor="#89CFF0"
|'''Postovulatory Week'''||'''Description'''||'''Image'''
|- bgcolor="#BCD4E6"
|'''Week 6''' ||
The surface of the developing tongue is covered by nearly flat epitheliuem (Figure 1) <ref name=PMID9455607/>. The first gustatory papillae of the tongue appears in the caudal midline near the foramen caecum and the first circumvallate papilla develop on the dorsal midline <ref name=PMID9455607/> .
||
image
|- bgcolor="#89CFF0"
| '''Weeks 6 to 7'''||
Nerve fibres approach the basal lamina of lingual epithelium <ref name=PMID8955790><pubmed>8955790</pubmed></ref>. At this stage the lingual epithelium consists of two to three cell layers and there is not yet any sign of cell specializations indicating early taste bud formation<ref name=PMID8955790/>.
||
Image
|- bgcolor="#BCD4E6"
| '''Week 7 '''||
A series of epithelial swellings in the anterior part and midline of the tongue indicate early forming fungiform papillae (figure 2) <ref name=PMID9455607/>.
||
Image
|- bgcolor="#89CFF0"
| ''' Week 8 ''' ||
The lingual epithelium shows first signs of taste bud development as nerve fibres penetrate epithelial basal lamina <ref name=PMID8955790/> and form synapses with taste bud progenitor cells. The synapses reach a maximum around the 12th to 13th week <ref name=PMID8955790/>. However, at this time these cells are still poorly differentiated, elongated epithelial cells <ref name=PMID8955790/> . The synapses demonstrate the neuronal connection between the taste bud primordium and the central nervous system <ref name=PMID8955790/>. Ciliated cells also appear around the 8th week, however the significance of these cells which are scattered randomly across the lingual surface remains unclear <ref name=PMID8955790/>.
||
Image
|- bgcolor="#BCD4E6"
|''' Weeks 8-9''' ||
“By this stage the top surface of circumvallate papillae usually contains a taste pit partly filled with microvilli of presumed underlying taste bud cells” (Figure 10) <ref name=PMID9455607/>
||
Image
|- bgcolor="#89CFF0"
|''' Weeks 10-11''' ||
At this stage, the lingual epithelium compromises of about four cell layers, and the first shallow grooves above the taste bud primordium are developed <ref name=PMID8955790/>.

Fungiform papillae appear on the lateral margins and the tip of the tongue <ref name=PMID9455607/>, containing taste bud primordial that display the first signs of a primitive pore formation <ref name=PMID8955790/>.

Untypically differentiated apical cellular processes extend onto the surface <ref name=PMID9455607/>

Some taste bud primordial contain cells that perforate the covering epithelial later with short, broad untypically differentiated apical cellular processes. (Figure 3,4) <ref name=PMID8955790/> <ref name=PMID9455607/>
||
Image
|- bgcolor="#BCD4E6"
|''' Week 12 ''' ||
Taste bud cells are more clearly differentiated into epithelial cell types II and III <ref name=PMID8955790/>.
||
Image
|- bgcolor="#89CFF0"
|''' Weeks 12-13 ''' ||
By this stage the taste bud primordial are all located on the top of dermal papillae (Fig 6a) <ref name=PMID8955790/>. There is also maximum synapses between cells and afferent nerve fibres, which intermingle with each other to form a plexus-like structure <ref name=PMID8955790/>.
||
Image
|- bgcolor="#BCD4E6"
|''' Weeks 14 -15 ''' ||
The shape of the taste buds primordial begins to resemble those of adult taste buds <ref name=PMID8955790/>. By the 14th week the taste pores develop as the taste pits are filled by microvilli <ref name=PMID8955790/>, indicating the possibility that the taste buds begin their gustatory function <ref name=PMID8955790/>, however they still lack an electron-dense mucous material (Fig.10) <ref name=PMID8955790/>. The tastebuds only achieve a fully developed function in week 15 of gestation with the development of type I cells to produce the mucous material in the taste pit <ref name=PMID8955790/>.
||
Image
|}

==History of Discoveries==

{| cellpadding=5 style="border:1px solid #BBB"
|- bgcolor="#faecc8"
|''' Date'''|| '''Significant Discovery'''
|- bgcolor="#faf6ed"
|'''350BC'''
|| Aristotle writes about the basic tastes, sweet and bitter, which can be modified, he says, by salty and acidic.
|- bgcolor="#faecc8"
|'''1901'''
|| D. Hanig publishes a paper containing data of taste sensitivity in different regions of the tongue. The data are later misinterpreted, giving rise to the myth of the ‘tongue map’

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''1908'''
|Fifth basic taste discovered: savouriness, described as umami, which is conferred by glutamate.

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''1931'''
|Bitter taste sensitivity found to vary among humans (1)

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''1931-32'''
|Genetecists confirm findings about sensitivity to bitter tasting PTC and discover non-tasting is a recessive genetic trait (2,11)

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''1939'''
|Geneticists show that chimpansees like humans, vary in their ability to perceive the bitterness of PTC

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''1992'''
|Discovery of gustucin, a teste cell-specific G-protein, in the taste buds. Gustucin is later shown to mark bitter, umami and sweet cells (13)

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''1996'''
| Witt M and Reutter K of the Source Department of Anatomy, Technical University Dresden, Germany, carried out a transmission electron microscopy study to investigate the embryonic and fetal development of Human taste buds. Their results suggest an "at least dual function of embryonic/fetal taste buds", including non-gustatory, paracrine functions prior to the 14th week and gustatory after the 14th week. PMID 8955790

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''2000'''
|First taste sonsors, the T2R receptors, discovered (3)

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''2001'''
|The sweet receptor is discovered (5): a combination of TaR2 and T1R3.

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''2002'''
|Amino acid detector, T1R1 and T1R3 identified (6) = Umami

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''2005'''
|Sweet taste receptor found (15) in the GI tract

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''2006'''
|Cells for sour taste discovered, identified by PKD2L1 (4-7)

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''2007'''
|Harlow DE, Barlow LA of the Department of Cell and Developmental Biology, Rocky Mountain Taste and Smell Center, University of Colorado Denver Health Sciences Center provide evidence of the '''embryonic origin of gustatory cranial sensory neurons''' PMID 17826760

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''2009'''
|The Car4 receptor, which senses the carbon dioxide in fizzy drinks is found on sour cells (8)

A study by Hevezi P et al, presents the first comprehensive characterization of gene expression in primate taste buds, as opposed to previous studies which focused on rodents. PMID 19636377

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''2010'''
|ENaC identified as the sodium-salt taste receptor (9)
|}

*[http://www.nature.com/nature/journal/v486/n7403_supp/fig_tab/486S2a_F1.html Gustatory system: The finer points of taste] <ref><pubmed>22717400</pubmed></ref>

==Adult Tongue and Taste Buds – Structure and Function==

'''Structure'''

The tongue is located on the floor of the oral cavity, It is a muscular structure with sensory units crowning. The tongue is divided into an anterior two thirds and a posterior one third. These regions are divided by a V-shaped groove at the back of the tongue (sulcus terminalis). The anterior two thirds of the tongue is covered by stratified squamous epithelium, It contains a roughened surface and has projections called papillae that vary in shape and number.

''''The Image Below is a very simplistic Diagram of the surface of the Tongue showing the locations of the different papillae and other important features'''

{|
| [[Image:Drawing of Tongue.png|500px]]

'''Papillae'''
[[File:Papillae.jpg|Left|thumb|200px|Close up of Human Tongue Papillae]]

There are 4 types of papillae on the tongue.
The most numerous papillae are the filiform papillae, which function to provide a surface that aids in holding food on the tongue during chewing but do not contain taste buds. The larger, less numerous fungiform papillae which contain taste buds, as do foliate papillae. Circumvallate papillae form a wide V at the sulcus terminalis also containing taste bus. There are no papillae or taste buds located on the posterior third of the tongue, having mucosal folds and the lingual tonsils instead.

'''Function'''

The tongue is for tasting, swallowing, and speech.
The functional unit of the taste bud is a taste cell, there are between 50 and 100 taste cells in each taste bud these taste cells represent all 5 different tastes. Historically is was believed that different areas of the tongue were responsible for different taste sensations although this has since been disregarded.[http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/W/Welcome.html] The papillae contain taste buds which are connected to the oral cavity via a taste pore, the function of the taste bud is to transmit a chemical signal from the oral cavity to a taste cell, this chemical signal is the converted into an electrical impulse and delivered to the brain via nerve fibres for interpretation.

'''The Image Below is a very simplistic Hand drawn Diagram of a taste bud, in an extreme close up, cross section view of the the taste bud unit, not to scale'''

[[File:Taste_bud_1.jpg]]

==Abnormalities==

===Knocking out P2X Receptors===

[[File:Image of taste being evoked by visualising ATP release.jpeg|Left|thumb|200px|Evoking taste - ATP release in tongue]]

Gustatory abnormalities has not been widely researched and what has been researched has been through animal testing, most commonly we have found on mice.

In Huang, 2008 this team used the release of the neurotransmitter, ATP (adenosine triphosphate) as a quantitative measurement of gustatory sensation and taste. This was done by using a comparison of wild type (WT) and double knockout (DKO) mice. P2X receptors, P2X2 and P2X3 were knocked out in the DKO mice. The premise of this article was that knocking out P2X receptors reduces transmitter secretion of ATP in taste buds, therefore they cannot taste.

It should be noted that the taste buds in DKO are functional, but are not stimulated by the administration of tastants.

The transmission of release of ATP is secretion through gap junction hemichannels (pannexin 1 gap junction).

When both P2X2 and P2X3 are knocked out, no taste is elicited. However they found that if either P2X2 OR P2X3 was knocked out there was a taste response. So the inference made from this is that if one of the two receptors from the P2X family was knocked out there still can have taste response. The WT mice showed significant stimulation by tastants whereas DKO had little to no stimulation of ATP release.<ref><pubmed>21940456</pubmed></ref>

===FGF signalling and genes===

Sprouty, or ''Srpy'', genes have been related to regulating the development of circumvillate papillae (CVP). The CVP are large dome shaped papillae, which form a 'V' just in front of the terminal sulcus.

By knocking out ''Spry'' genes using mice which had ''Spry1'' and ''Spry2'' knocked out showed that the number of CVP doubled. However, when Fibroblast Growth Factor gene ("Fgf10") was absent, the number of CVP was significantly reduced, if not completely absent. The correlation between ''Spry1/2'' and ''Fgf10'' is that ''Spry1/2'' antagonises "Fgf10" to limit the size of the CVP progenitor placode. Exclusive expression of ''Fgf10'' in the mesenchyme is necessary for the formation of CVP.

'''This image shows the CVP stained with H&E and scanned by Scanning Electron Microscope (SEM)'''
[[File:CVP of WT(top) and DKO(bottom) mice with H&E and SEM.png]]

'''This image shows the location of the CVP and the increased number in DKO mice by SEM'''
[[File:Mouse circumvallate papilla 01.jpg|300px]]

Taste buds develop from the mesenchyme but require local signalling to properly differentiate. Some signalling factors for proper development of taste buds besides FGF are: Sonic Hedgehog (SHH), Bone Morphogenetic Proteins (BMPs), Epidermal Growth Factor (EGF).

Additionally, this proves that the anterior and posterior developments of the tongue are derived from embryonic tissues, where the anterior tongue is derived from the ectoderm and the posterior tongue is derived from the endoderm. Taste buds develop from the mesenchyme but require local signalling to properly differentiate. Some signalling factors for proper development of taste buds besides FGF are: Sonic Hedgehog (SHH), Bone Morphogenetic Proteins (BMPs), Epidermal Growth Factor (EGF).

As mentioned above, this article shows that the anterior and posterior developments of the tongue are derived from embryonic tissues, where the anterior tongue is derived front the ectoderm and the posterior tongue is derived from the endoderm. Secondly, FGF is required to regulate the growth of taste buds, while ''Spry'' genes limit the number of CVP. ''Fgf10''& ''Spry 1&2''work antagonistically through receptor tyrosine kinase (RTK)signalling.

However, the deletion of ''Spry2''led to the increase of CVPs it should be noted that they found that a significant decrease in number of fungiform papillae. Contrastingly, the absence of ''Fgf10'', while leading to the absence of CVPs lead to an increase in number and size of fungiform papillae. Therefore these genes have different effects on the anterior and posterior developing tongue and taste buds.<ref><pubmed>21655085</pubmed></ref>

==Current Research==
We have an evolving understanding of Embryonic Taste development, through the use of state-of-the-art technology and research techniques we are able to make brilliant discoveries that continue to connect the dots of this amazing natural process of human development.
The majority of research in taste development is involving mice, these mammals show similar embryonic pathways to humans and research is performed in ethical and humane methods.

'''the below image shows histological stains of a mice tongue showing dysplasia"

[[File:Histology.jpg]]

'''Synergistic relationships of Six Genes '''

In an animal study using mice by Suzuki Y, Ikeda K, Kawakami K.(2011) Firstly nominating "Six Genes" as a major component in gustatory development, stating that deficiencies in certain Six genes (specifically Six1 & Six4) leads to poor development. Their research also highlights evidence of cooperative relationships between Six genes for normal advance. This experiment involved breeding mice containing exclusively Six1 and Six4 genes and examining the expression of these genes in papillae under high powered microscope observation. Understanding the role of certain genes along with the intrinsic relationships they hold is crucial for the ability to identify possible causes and correction of any abnormalities <ref><pubmed>21978088</pubmed></ref>

'''Neural Crest responsibilities '''

Another Animal Study involving mice explores a new idea of Neural crest (NC) contribution in taste development, specifically the development of papillae and taste buds. Liu HX, Komatsu Y, Mishina Y, Mistretta CM. (2012) suggest that Neural crest cells travel to the location of the tongue in early embryonic stages, gain epithelium phenotypes, multiply and then differentiate to eventually form taste papillae. The experiment involved the comparison of 2 different types of Cre line mice, which both express Cre gene in neural crest protocol, the different distribution patterns where observed in specific regions that NC is responsible for.<ref><pubmed>22659543</pubmed></ref>

'''Augmentation of Endoderm'''

In an animal study conducted by Rothova M, Thompson H, Lickert H, Tucker AS.(2012) exploring the historically debated issue of endoderm contribution to tongue development showed promising evidence that position of taste buds are patterned by the border of ectoderm and endoderm derivative epithelium. This study was accomplished via microscopic examination of previously stained specimens. Concluding endoderm has direct influence on gustatory develoment <ref><pubmed>22581563</pubmed></ref>

'''Changes in Taste Cells over time'''

Research by
Ozdener H, Spielman AI, Rawson NE.(2012) developing a culture which allows taste cells to survive for up to 12 months, empowers researchers to study the processes of proliferation, differentiation and function. This experiment will provide a precidnet for future study of taste cells, as these cells are able to operate and grow normally. <ref><pubmed>22643728</pubmed></ref>

'''Shh key component of taste bud proginators'''

A tamoxifen treatment which supresses Sonic hedgehog (Shh) secretion in mice proving to reduce the number of cells visable within papillae, in contrast mice not treated with tamoxifen showed a mark increase of cells within papillae, these cells are assumed to become taste cells in later development.
Specific mice were bred to trace the destination of taste placode cells, the study concluded that Shh expressing placodes are taste bud proginators which in turn become taste cells within taste buds although do not have any prescuros relationship with pappilae. The results were obtain by examination of mice embryos using Bright-field or multichannel fluorescent images through the use of an "Axiocam CCD camera and Axioplan fluorescence microscope with Axiovision software" a study by Harlow, Yang, Williams, Barlow (2011)<ref><pubmed>PMC2674259</pubmed></ref>

'''WNT family exhibit various roles'''

The WNT gene family has a function of signally proteins for various reason such as development, In 2010 Liu, Staubach Grosse, Walton, Saims, Gumucio, Mistretta explored recent findings on the role of WNT's in tongue and papillae development, Concluding that WNT/β-catenin is essential for fungiform papillae differing to WNT5a which proved to be principle in tongue development. Intrinsic chemical mediators were considered by manipulating a tissue culture and then throughaly examined by scanning photomicrograph. <ref><pubmed>PMC2768563</pubmed></ref>

'''The below image shows and example of tongue abnormalities, this is called "double tongue" each side has independent movement'''
[http://www.surgicalneurologyint.com/article.asp?issn=2152-7806;year=2012;volume=3;issue=1;spage=23;epage=23;aulast=Manjila]
[[File:Abnormal of tongue.jpg]]

==Useful links==

==Glossary==

ectoderm- outer germ layer of embryo

endoderm - inner germ layer of embryo

epithelium - basic animal tissue that is composed of tightly packed cells, usually covering the outer portion of organs

exocystosis - movement of contents out of cell

ganglia - the accumulation of a nerve cell body

growth factor - a substance that stimulates the growth of cells

gustatory - anything that relates to the taste sense

hydrolysis - breakdown of a chemical when it reacts with water

mesoderm - middle germ layer of embryo

mesenchyme - multipotential cells

neural crest - a part of the ectoderm found on both sides of the neural tube

neuron - most simplistic unit of the nervous system

neurotransmitter - chemicals which allow the passing of signals from neuron to neuron via connecting part (synapse)

papillae - small rough surface projection

six genes - a family of genes

Sonic hedgehog (Shh) - signalling protein invloved in normal development

sulcus terminalis - describes a physical transition point separating the anterior 2/3 of the tongue from the posterior 1/3

tamoxifen - hormonal altering drug

==Image gallery==

== References ==
<references/>

==External Links==
{{External Links}}

--[[User:Z8600021|Mark Hill]] 12:22, 15 August 2012 (EST) Please leave the content listed below the line at the bottom of your project page.

----

{{2012Projects}}

File:Taste map.png

2012-09-25T12:58:11Z

Z3330986: The outdated concept of a 'tongue map' which suggests different taste qualities are region specific on the surface of the tongue

The outdated concept of a 'tongue map' which suggests different taste qualities are region specific on the surface of the tongue

File:Primary gustatory cortex.png

2012-09-25T12:16:30Z

Z3330986: /* Primary gustatory cortex */

==Primary gustatory cortex==
Diagram showing the insular cortex and approximate location of the primary gustatory area

==Copyright information==

This image is a student annotated image sourced from ''Brainstorm: The interactive guide to Human anatomy'' Version 6.32 (Java). Copyright (c) Elizabeth Tancred 1991 - 2005

2012 Group Project 3

2012-09-25T12:10:42Z

Z3330986: /* Taste Map */

=Taste Development=

==Gustatory System==

===Introduction===

[[Image:Taste qualities.gif|thumb|The five basic tastes]]

Taste or more appropriately gustation, is a fundamental survival tool in animals as it directs the consumption of essential nutrients. The five tastes that exist within the human gustatory system: salty, sweet, sour, bitter and umami, all signify basic physiological requirements. Salty tastes denote the presence of Na+, an important ion involved in the transportation and retention of water across cell membranes. Sweetness is the recognition of carbohydrates, essential for maintaining optimal brain function and providing the basis for energy production in muscle tissue via ATP hydrolysis. Similarly umami codes for the presence of L-amino acids, especially L-glutamate which is an integral component of protein synthesis.

These different modalities not only function to maintain the proper intake of nutrients within the body but also, by way of aversion, prohibit the consumption of undesired or poisonous materials. The bitter modality for example is generally regarded as displeasing to the human palate. It represents a high acid content which may be a result of foods which have become rotten or are inherently poisonous to the body.<ref name=PMID20696704><pubmed>20696704</pubmed></ref>

Research has historically limited itself to investigating the mechanisms of these five taste qualities though it must be noted many other modalities may exist. Of particular conjecture is the existence of fatty acid recognition. In the past the detection of fat in food has been attributed to somatosensory inputs <ref name=PMID20696704/> from the tongue, that is, the oily feel and texture of fat rather than its actual ‘taste’ allows the brain to encode for its presence. Further research is therefore required to elicit the precise mechanisms of fat detection.

===Cell Biology===

The five taste qualities are not all detected by the same type of receptor cell located within the taste bud. Like rods and cones in the eye which detect different wavelengths of light, there are specific types of receptors for different tastes. For example, sweet, umami and bitter are recognised by Type II G-protein coupled receptors, whereas sour is related to Type III presynaptic cells. The cell type involved in salty taste transduction is unknown however it is known that sodium ions can enter the receptor cell membrane via ion channel permeation.

====Type II receptors====

When a bitter, sweet or umami ligand binds to a type II G-coupled receptor, a cascade of chemical reactions causes the release of Ca2+ which in turn mediates exocystosis of ATP. The function of this ATP is threefold:

# Stimulates gustatory nerve afferents which project to gustatory nuclei in the spinal cord
# Excites Type III presynaptic nerve fibres to release serotonin.
# Has a positive feedback effect on type II receptor cells, increasing the level of ATP production.

The role of serotonin is believed to be in the form of lateral inhibition i.e. when a bitter quality is recognised, adjacent receptors for sweetness are deactivated and thus the two tastes may be clearly differentiated. It also has a negative feedback effect on receptor cells, inhibiting umami, bitter and sweet taste transduction.

==Taste Map==

The idea of a tongue map has disseminated through society for many years. This concept purports that different areas of the tongue are specialised to detect either sweet, salty, sour and bitter tastes. Recent research however has completely nullified such claims and suggests instead that different forms of taste are recognised all over the tongue as well as via the palate. Thus the term ''taste map'' has come to take on a new meaning and that is, the precise areas of taste modalities processing in areas of cortex and its subsequent neural inputs.

===Neural Pathways===

'''First order neurons''' - From the receptors located in the taste buds, gustatory nerve afferents project to the ipsilateral rostral 1/3 of the nucleus tractus solitarius (NTS), located in the medulla. This rostral 1/3 is commonly referred to as the ''gustatory nucleus''.

The ''gustatory nucleus'' receives input from cranial nerves VII (''Facial n.''), IX (''Hypglossal n.''), and X (''Vagus n.'') via special visceral afferent (SVA) nerve fibres. A summary of their functions is as follows:

* ''Facial nerve n''. - carries taste information from the anterior 2/3 of the tongue.
* ''Hypoglossal n.'' - carries taste information from the posterior 1/3 of the tongue.
* ''Vagus n''. - carries taste information from the palate

'''Second order neurons''' - From the NTS second order neurons carry taste information to the Ventral posteromedial (VPM) nucleus in the thalamus.<ref name=PMID21885776/>

Copious scientific conjecture surrounds how each taste modality is transmitted to the brain. The ‘labelled-line’ hypothesis suggests that there are taste specific neurons which exclusively carry that taste modality to cortical areas. In analogous terms it can be viewed like the pipelines leading toward a house. Each pipeline carries its own utility, there is one for gas, another for water and finally for electricity with each terminating in slightly different areas of the house. In the same way, on the tongues there are different receptors for each taste which concurrently have individual nerve tracts leading to the primary gustatory cortex.

Contrapuntally there is electrophysiological evidence that single nerve afferents carry multiple modalities. These studies show one nerve afferent may have both a strong and a weak activation in response to a multiple taste stimuli.

===Cortical Areas===

[[Image:Primary gustatory cortex.png|thumb|Primary gustatory cortex]]

The location of the taste perception centres has been observed via functional magnetic resonance imaging (fMRI) studies. The primary taste cortex has been identified as being located in the anterior insula/frontal operculum (I/fO)<ref name=PMID22245354><pubmed>22245354</pubmed></ref>, with the secondary taste cortex in the caudolateral orbitofrontal cortex.<ref name=PMID21305668><pubmed>21305668</pubmed></ref> Within the insula there are further subdivisions related to each taste modality. Two photon calcium imaging research has outlined certain ’hot-spots’ of activation which are clearly delineated in relation to each taste. For example, the bitter modality is represented on the insula cortex approximately 1mm posterior to the middle cerebral artery whereas the sweet modality is represented 2.5mm rostrodorsal to the bitter field with no apparent overlap.<ref name=PMID21885776><pubmed>21885776</pubmed></ref> These findings lend weight to the idea that there is only one receptor for each taste quality.

It is interesting to note the relationship between taste and the reward centres of the brain. There is evidence of neural input to the ventral tegmental area (the origin of the mesolimbic dopaminergic reward pathway) and nucleus accumbens (involved in the conversion of motivation into physical action).<ref name=PMID21885776/> Neural connections such as this provide the foundations in explaining concepts such as flavour learning and preference. It may also give some insight into chronic problems such as food addiction and craving. As of yet however the gustatory neural network is not well understood and more research is required to elucidate the relationship between pleasure and taste sensation

==Timeline of Developmental Processes of the Gustatory System==

{| cellpadding=5 style="border:1px solid #BBB"
|- bgcolor="#89CFF0"
|'''Postovulatory Week'''||'''Description'''||'''Image'''
|- bgcolor="#BCD4E6"
|'''Week 6''' ||
The surface of the developing tongue is covered by nearly flat epitheliuem (Figure 1) <ref name=PMID9455607/>. The first gustatory papillae of the tongue appears in the caudal midline near the foramen caecum and the first circumvallate papilla develop on the dorsal midline <ref name=PMID9455607/> .
||
image
|- bgcolor="#89CFF0"
| '''Weeks 6 to 7'''||
Nerve fibres approach the basal lamina of lingual epithelium <ref name=PMID8955790><pubmed>8955790</pubmed></ref>. At this stage the lingual epithelium consists of two to three cell layers and there is not yet any sign of cell specializations indicating early taste bud formation<ref name=PMID8955790/>.
||
Image
|- bgcolor="#BCD4E6"
| '''Week 7 '''||
A series of epithelial swellings in the anterior part and midline of the tongue indicate early forming fungiform papillae (figure 2) <ref name=PMID9455607/>.
||
Image
|- bgcolor="#89CFF0"
| ''' Week 8 ''' ||
The lingual epithelium shows first signs of taste bud development as nerve fibres penetrate epithelial basal lamina <ref name=PMID8955790/> and form synapses with taste bud progenitor cells. The synapses reach a maximum around the 12th to 13th week <ref name=PMID8955790/>. However, at this time these cells are still poorly differentiated, elongated epithelial cells <ref name=PMID8955790/> . The synapses demonstrate the neuronal connection between the taste bud primordium and the central nervous system <ref name=PMID8955790/>. Ciliated cells also appear around the 8th week, however the significance of these cells which are scattered randomly across the lingual surface remains unclear <ref name=PMID8955790/>.
||
Image
|- bgcolor="#BCD4E6"
|''' Weeks 8-9''' ||
“By this stage the top surface of circumvallate papillae usually contains a taste pit partly filled with microvilli of presumed underlying taste bud cells” (Figure 10) <ref name=PMID9455607/>
||
Image
|- bgcolor="#89CFF0"
|''' Weeks 10-11''' ||
At this stage, the lingual epithelium compromises of about four cell layers, and the first shallow grooves above the taste bud primordium are developed <ref name=PMID8955790/>.

Fungiform papillae appear on the lateral margins and the tip of the tongue <ref name=PMID9455607/>, containing taste bud primordial that display the first signs of a primitive pore formation <ref name=PMID8955790/>.

Untypically differentiated apical cellular processes extend onto the surface <ref name=PMID9455607/>

Some taste bud primordial contain cells that perforate the covering epithelial later with short, broad untypically differentiated apical cellular processes. (Figure 3,4) <ref name=PMID8955790/> <ref name=PMID9455607/>
||
Image
|- bgcolor="#BCD4E6"
|''' Week 12 ''' ||
Taste bud cells are more clearly differentiated into epithelial cell types II and III <ref name=PMID8955790/>.
||
Image
|- bgcolor="#89CFF0"
|''' Weeks 12-13 ''' ||
By this stage the taste bud primordial are all located on the top of dermal papillae (Fig 6a) <ref name=PMID8955790/>. There is also maximum synapses between cells and afferent nerve fibres, which intermingle with each other to form a plexus-like structure <ref name=PMID8955790/>.
||
Image
|- bgcolor="#BCD4E6"
|''' Weeks 14 -15 ''' ||
The shape of the taste buds primordial begins to resemble those of adult taste buds <ref name=PMID8955790/>. By the 14th week the taste pores develop as the taste pits are filled by microvilli <ref name=PMID8955790/>, indicating the possibility that the taste buds begin their gustatory function <ref name=PMID8955790/>, however they still lack an electron-dense mucous material (Fig.10) <ref name=PMID8955790/>. The tastebuds only achieve a fully developed function in week 15 of gestation with the development of type I cells to produce the mucous material in the taste pit <ref name=PMID8955790/>.
||
Image
|}

==History of Discoveries==

{| cellpadding=5 style="border:1px solid #BBB"
|- bgcolor="#faecc8"
|''' Date'''|| '''Significant Discovery'''
|- bgcolor="#faf6ed"
|'''350BC'''
|| Aristotle writes about the basic tastes, sweet and bitter, which can be modified, he says, by salty and acidic.
|- bgcolor="#faecc8"
|'''1901'''
|| D. Hanig publishes a paper containing data of taste sensitivity in different regions of the tongue. The data are later misinterpreted, giving rise to the myth of the ‘tongue map’

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''1908'''
|Fifth basic taste discovered: savouriness, described as umami, which is conferred by glutamate.

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''1931'''
|Bitter taste sensitivity found to vary among humans (1)

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''1931-32'''
|Genetecists confirm findings about sensitivity to bitter tasting PTC and discover non-tasting is a recessive genetic trait (2,11)

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''1939'''
|Geneticists show that chimpansees like humans, vary in their ability to perceive the bitterness of PTC

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''1992'''
|Discovery of gustucin, a teste cell-specific G-protein, in the taste buds. Gustucin is later shown to mark bitter, umami and sweet cells (13)

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''1996'''
| Witt M and Reutter K of the Source Department of Anatomy, Technical University Dresden, Germany, carried out a transmission electron microscopy study to investigate the embryonic and fetal development of Human taste buds. Their results suggest an "at least dual function of embryonic/fetal taste buds", including non-gustatory, paracrine functions prior to the 14th week and gustatory after the 14th week. PMID 8955790

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''2000'''
|First taste sonsors, the T2R receptors, discovered (3)

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''2001'''
|The sweet receptor is discovered (5): a combination of TaR2 and T1R3.

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''2002'''
|Amino acid detector, T1R1 and T1R3 identified (6) = Umami

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''2005'''
|Sweet taste receptor found (15) in the GI tract

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''2006'''
|Cells for sour taste discovered, identified by PKD2L1 (4-7)

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''2007'''
|Harlow DE, Barlow LA of the Department of Cell and Developmental Biology, Rocky Mountain Taste and Smell Center, University of Colorado Denver Health Sciences Center provide evidence of the '''embryonic origin of gustatory cranial sensory neurons''' PMID 17826760

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''2009'''
|The Car4 receptor, which senses the carbon dioxide in fizzy drinks is found on sour cells (8)

A study by Hevezi P et al, presents the first comprehensive characterization of gene expression in primate taste buds, as opposed to previous studies which focused on rodents. PMID 19636377

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''2010'''
|ENaC identified as the sodium-salt taste receptor (9)
|}

*[http://www.nature.com/nature/journal/v486/n7403_supp/fig_tab/486S2a_F1.html Gustatory system: The finer points of taste] <ref><pubmed>22717400</pubmed></ref>

==Adult Tongue and Taste Buds – Structure and Function==

'''Structure'''

The tongue is located on the floor of the oral cavity, It is a muscular structure with sensory units crowning. The tongue is divided into an anterior two thirds and a posterior one third. These regions are divided by a V-shaped groove at the back of the tongue (sulcus terminalis). The anterior two thirds of the tongue is covered by stratified squamous epithelium, It contains a roughened surface and has projections called papillae that vary in shape and number.

''''The Image Below is a very simplistic Diagram of the surface of the Tongue showing the locations of the different papillae and other important features'''

{|
| [[Image:Drawing of Tongue.png|500px]]

'''Papillae'''
[[File:Papillae.jpg|Left|thumb|200px|Close up of Human Tongue Papillae]]

There are 4 types of papillae on the tongue.
The most numerous papillae are the filiform papillae, which function to provide a surface that aids in holding food on the tongue during chewing but do not contain taste buds. The larger, less numerous fungiform papillae which contain taste buds, as do foliate papillae. Circumvallate papillae form a wide V at the sulcus terminalis also containing taste bus. There are no papillae or taste buds located on the posterior third of the tongue, having mucosal folds and the lingual tonsils instead.

'''Function'''

The tongue is for tasting, swallowing, and speech.
The functional unit of the taste bud is a taste cell, there are between 50 and 100 taste cells in each taste bud these taste cells represent all 5 different tastes. Historically is was believed that different areas of the tongue were responsible for different taste sensations although this has since been disregarded.[http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/W/Welcome.html] The papillae contain taste buds which are connected to the oral cavity via a taste pore, the function of the taste bud is to transmit a chemical signal from the oral cavity to a taste cell, this chemical signal is the converted into an electrical impulse and delivered to the brain via nerve fibres for interpretation.

'''The Image Below is a very simplistic Hand drawn Diagram of a taste bud, in an extreme close up, cross section view of the the taste bud unit, not to scale'''

[[File:Taste_bud_1.jpg]]

==Abnormalities==

===Knocking out P2X Receptors===

[[File:Image of taste being evoked by visualising ATP release.jpeg|Left|thumb|200px|Evoking taste - ATP release in tongue]]

Gustatory abnormalities has not been widely researched and what has been researched has been through animal testing, most commonly we have found on mice.

In Huang, 2008 this team used the release of the neurotransmitter, ATP (adenosine triphosphate) as a quantitative measurement of gustatory sensation and taste. This was done by using a comparison of wild type (WT) and double knockout (DKO) mice. P2X receptors, P2X2 and P2X3 were knocked out in the DKO mice. The premise of this article was that knocking out P2X receptors reduces transmitter secretion of ATP in taste buds, therefore they cannot taste.

It should be noted that the taste buds in DKO are functional, but are not stimulated by the administration of tastants.

The transmission of release of ATP is secretion through gap junction hemichannels (pannexin 1 gap junction).

When both P2X2 and P2X3 are knocked out, no taste is elicited. However they found that if either P2X2 OR P2X3 was knocked out there was a taste response. So the inference made from this is that if one of the two receptors from the P2X family was knocked out there still can have taste response. The WT mice showed significant stimulation by tastants whereas DKO had little to no stimulation of ATP release.<ref><pubmed>21940456</pubmed></ref>

===FGF signalling and genes===

Sprouty, or ''Srpy'', genes have been related to regulating the development of circumvillate papillae (CVP). The CVP are large dome shaped papillae, which form a 'V' just in front of the terminal sulcus.

By knocking out ''Spry'' genes using mice which had ''Spry1'' and ''Spry2'' knocked out showed that the number of CVP doubled. However, when Fibroblast Growth Factor gene ("Fgf10") was absent, the number of CVP was significantly reduced, if not completely absent. The correlation between ''Spry1/2'' and ''Fgf10'' is that ''Spry1/2'' antagonises "Fgf10" to limit the size of the CVP progenitor placode. Exclusive expression of ''Fgf10'' in the mesenchyme is necessary for the formation of CVP.

'''This image shows the CVP stained with H&E and scanned by Scanning Electron Microscope (SEM)'''
[[File:CVP of WT(top) and DKO(bottom) mice with H&E and SEM.png]]

'''This image shows the location of the CVP and the increased number in DKO mice by SEM'''
[[File:Mouse circumvallate papilla 01.jpg|300px]]

Taste buds develop from the mesenchyme but require local signalling to properly differentiate. Some signalling factors for proper development of taste buds besides FGF are: Sonic Hedgehog (SHH), Bone Morphogenetic Proteins (BMPs), Epidermal Growth Factor (EGF).

Additionally, this proves that the anterior and posterior developments of the tongue are derived from embryonic tissues, where the anterior tongue is derived from the ectoderm and the posterior tongue is derived from the endoderm. Taste buds develop from the mesenchyme but require local signalling to properly differentiate. Some signalling factors for proper development of taste buds besides FGF are: Sonic Hedgehog (SHH), Bone Morphogenetic Proteins (BMPs), Epidermal Growth Factor (EGF).

As mentioned above, this article shows that the anterior and posterior developments of the tongue are derived from embryonic tissues, where the anterior tongue is derived front the ectoderm and the posterior tongue is derived from the endoderm. Secondly, FGF is required to regulate the growth of taste buds, while ''Spry'' genes limit the number of CVP. ''Fgf10''& ''Spry 1&2''work antagonistically through receptor tyrosine kinase (RTK)signalling.

However, the deletion of ''Spry2''led to the increase of CVPs it should be noted that they found that a significant decrease in number of fungiform papillae. Contrastingly, the absence of ''Fgf10'', while leading to the absence of CVPs lead to an increase in number and size of fungiform papillae. Therefore these genes have different effects on the anterior and posterior developing tongue and taste buds.<ref><pubmed>21655085</pubmed></ref>

==Current Research==
We have an evolving understanding of Embryonic Taste development, through the use of state-of-the-art technology and research techniques we are able to make brilliant discoveries that continue to connect the dots of this amazing natural process of human development.
The majority of research in taste development is involving mice, these mammals show similar embryonic pathways to humans and research is performed in ethical and humane methods.

'''the below image shows histological stains of a mice tongue showing dysplasia"

[[File:Histology.jpg]]

'''Synergistic relationships of Six Genes '''

In an animal study using mice by Suzuki Y, Ikeda K, Kawakami K.(2011) Firstly nominating "Six Genes" as a major component in gustatory development, stating that deficiencies in certain Six genes (specifically Six1 & Six4) leads to poor development. Their research also highlights evidence of cooperative relationships between Six genes for normal advance. This experiment involved breeding mice containing exclusively Six1 and Six4 genes and examining the expression of these genes in papillae under high powered microscope observation. Understanding the role of certain genes along with the intrinsic relationships they hold is crucial for the ability to identify possible causes and correction of any abnormalities <ref><pubmed>21978088</pubmed></ref>

'''Neural Crest responsibilities '''

Another Animal Study involving mice explores a new idea of Neural crest (NC) contribution in taste development, specifically the development of papillae and taste buds. Liu HX, Komatsu Y, Mishina Y, Mistretta CM. (2012) suggest that Neural crest cells travel to the location of the tongue in early embryonic stages, gain epithelium phenotypes, multiply and then differentiate to eventually form taste papillae. The experiment involved the comparison of 2 different types of Cre line mice, which both express Cre gene in neural crest protocol, the different distribution patterns where observed in specific regions that NC is responsible for.<ref><pubmed>22659543</pubmed></ref>

'''Augmentation of Endoderm'''

In an animal study conducted by Rothova M, Thompson H, Lickert H, Tucker AS.(2012) exploring the historically debated issue of endoderm contribution to tongue development showed promising evidence that position of taste buds are patterned by the border of ectoderm and endoderm derivative epithelium. This study was accomplished via microscopic examination of previously stained specimens. Concluding endoderm has direct influence on gustatory develoment <ref><pubmed>22581563</pubmed></ref>

'''Changes in Taste Cells over time'''

Research by
Ozdener H, Spielman AI, Rawson NE.(2012) developing a culture which allows taste cells to survive for up to 12 months, empowers researchers to study the processes of proliferation, differentiation and function. This experiment will provide a precidnet for future study of taste cells, as these cells are able to operate and grow normally. <ref><pubmed>22643728</pubmed></ref>

'''Shh key component of taste bud proginators'''

A tamoxifen treatment which supresses Sonic hedgehog (Shh) secretion in mice proving to reduce the number of cells visable within papillae, in contrast mice not treated with tamoxifen showed a mark increase of cells within papillae, these cells are assumed to become taste cells in later development.
Specific mice were bred to trace the destination of taste placode cells, the study concluded that Shh expressing placodes are taste bud proginators which in turn become taste cells within taste buds although do not have any prescuros relationship with pappilae. The results were obtain by examination of mice embryos using Bright-field or multichannel fluorescent images through the use of an "Axiocam CCD camera and Axioplan fluorescence microscope with Axiovision software" a study by Harlow, Yang, Williams, Barlow (2011)<ref><pubmed>PMC2674259</pubmed></ref>

'''WNT family exhibit various roles'''

The WNT gene family has a function of signally proteins for various reason such as development, In 2010 Liu, Staubach Grosse, Walton, Saims, Gumucio, Mistretta explored recent findings on the role of WNT's in tongue and papillae development, Concluding that WNT/β-catenin is essential for fungiform papillae differing to WNT5a which proved to be principle in tongue development. Intrinsic chemical mediators were considered by manipulating a tissue culture and then throughaly examined by scanning photomicrograph. <ref><pubmed>PMC2768563</pubmed></ref>

'''The below image shows and example of tongue abnormalities, this is called "double tongue" each side has independent movement'''
[http://www.surgicalneurologyint.com/article.asp?issn=2152-7806;year=2012;volume=3;issue=1;spage=23;epage=23;aulast=Manjila]
[[File:Abnormal of tongue.jpg]]

==Useful links==

==Glossary==

ectoderm- outer germ layer of embryo

endoderm - inner germ layer of embryo

epithelium - basic animal tissue that is composed of tightly packed cells, usually covering the outer portion of organs

exocystosis - movement of contents out of cell

ganglia - the accumulation of a nerve cell body

growth factor - a substance that stimulates the growth of cells

gustatory - anything that relates to the taste sense

hydrolysis - breakdown of a chemical when it reacts with water

mesoderm - middle germ layer of embryo

mesenchyme - multipotential cells

neural crest - a part of the ectoderm found on both sides of the neural tube

neuron - most simplistic unit of the nervous system

neurotransmitter - chemicals which allow the passing of signals from neuron to neuron via connecting part (synapse)

papillae - small rough surface projection

six genes - a family of genes

Sonic hedgehog (Shh) - signalling protein invloved in normal development

sulcus terminalis - describes a physical transition point separating the anterior 2/3 of the tongue from the posterior 1/3

tamoxifen - hormonal altering drug

==Image gallery==

== References ==
<references/>

==External Links==
{{External Links}}

--[[User:Z8600021|Mark Hill]] 12:22, 15 August 2012 (EST) Please leave the content listed below the line at the bottom of your project page.

----

{{2012Projects}}

File:Taste qualities.gif

2012-09-25T12:08:51Z

Z3330986: /* Copyright information */

==Taste qualities==
Taste qualities, the taste receptors that detect them, and examples
of natural stimuli. Five recognized taste qualities—sweet, sour,
bitter, salty, and umami—are detected by taste buds. Bitter taste is thought
to protect against ingesting poisons, many of which taste bitter. Sweet
taste signals sugars and carbohydrates. Umami taste is elicited by l-amino
acids and nucleotides. Salty taste is generated mainly by Na+ and sour
taste potently by organic acids. Evidence is mounting that fat may also
be detected by taste buds via dedicated receptors. The names of taste receptors
and cartoons depicting their transmembrane topology are shown
outside the perimeter. Bitter is transduced by G protein–coupled receptors
similar to Class I GPCRs (with short extracellular N termini). In contrast,
sweet and umami are detected by dimers of Class III GPCRs (with long
N termini that form a globular extracellular ligand-binding domain). One of
the receptors for Na+ salts is a cation channel composed of three subunits,
each with two transmembrane domains. Membrane receptors for sour and
fat are as yet uncertain.<ref name=PMID20696704><pubmed>20696704</pubmed></ref>

==Copyright information==
© 2010 Chaudhari and Roper This article is distributed under the terms of an Attribution–
Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication
date (see http://www.rupress.org/terms). After six months it is available under a
Creative Commons License (Attribution–Noncommercial–Share Alike 3.0 Unported license,
as described at http://creativecommons.org/licenses/by-nc-sa/3.0/).

==References==
1. Nirupa Chaudhari, Stephen D Roper The cell biology of taste. J. Cell Biol.: 2010, 190(3);285-96 PMID:20696704

2012 Group Project 3

2012-09-25T12:07:42Z

Z3330986: /* Introduction */

=Taste Development=

==Gustatory System==

===Introduction===

[[Image:Taste qualities.gif|thumb|The five basic tastes]]

Taste or more appropriately gustation, is a fundamental survival tool in animals as it directs the consumption of essential nutrients. The five tastes that exist within the human gustatory system: salty, sweet, sour, bitter and umami, all signify basic physiological requirements. Salty tastes denote the presence of Na+, an important ion involved in the transportation and retention of water across cell membranes. Sweetness is the recognition of carbohydrates, essential for maintaining optimal brain function and providing the basis for energy production in muscle tissue via ATP hydrolysis. Similarly umami codes for the presence of L-amino acids, especially L-glutamate which is an integral component of protein synthesis.

These different modalities not only function to maintain the proper intake of nutrients within the body but also, by way of aversion, prohibit the consumption of undesired or poisonous materials. The bitter modality for example is generally regarded as displeasing to the human palate. It represents a high acid content which may be a result of foods which have become rotten or are inherently poisonous to the body.<ref name=PMID20696704><pubmed>20696704</pubmed></ref>

Research has historically limited itself to investigating the mechanisms of these five taste qualities though it must be noted many other modalities may exist. Of particular conjecture is the existence of fatty acid recognition. In the past the detection of fat in food has been attributed to somatosensory inputs <ref name=PMID20696704/> from the tongue, that is, the oily feel and texture of fat rather than its actual ‘taste’ allows the brain to encode for its presence. Further research is therefore required to elicit the precise mechanisms of fat detection.

===Cell Biology===

The five taste qualities are not all detected by the same type of receptor cell located within the taste bud. Like rods and cones in the eye which detect different wavelengths of light, there are specific types of receptors for different tastes. For example, sweet, umami and bitter are recognised by Type II G-protein coupled receptors, whereas sour is related to Type III presynaptic cells. The cell type involved in salty taste transduction is unknown however it is known that sodium ions can enter the receptor cell membrane via ion channel permeation.

====Type II receptors====

When a bitter, sweet or umami ligand binds to a type II G-coupled receptor, a cascade of chemical reactions causes the release of Ca2+ which in turn mediates exocystosis of ATP. The function of this ATP is threefold:

# Stimulates gustatory nerve afferents which project to gustatory nuclei in the spinal cord
# Excites Type III presynaptic nerve fibres to release serotonin.
# Has a positive feedback effect on type II receptor cells, increasing the level of ATP production.

The role of serotonin is believed to be in the form of lateral inhibition i.e. when a bitter quality is recognised, adjacent receptors for sweetness are deactivated and thus the two tastes may be clearly differentiated. It also has a negative feedback effect on receptor cells, inhibiting umami, bitter and sweet taste transduction.

==Taste Map==

[[File:Tongue map.jpg|left|thumb|197px|The traditional tongue map concept]]
The idea of a tongue map has disseminated through society for many years. This concept purports that different areas of the tongue are specialised to detect either sweet, salty, sour and bitter tastes. Recent research however has completely nullified such claims and suggests instead that different forms of taste are recognised all over the tongue as well as via the palate. Thus the term ''taste map'' has come to take on a new meaning and that is, the precise areas of taste modalities processing in areas of cortex and its subsequent neural inputs.

===Neural Pathways===

'''First order neurons''' - From the receptors located in the taste buds, gustatory nerve afferents project to the ipsilateral rostral 1/3 of the nucleus tractus solitarius (NTS), located in the medulla. This rostral 1/3 is commonly referred to as the ''gustatory nucleus''.

The ''gustatory nucleus'' receives input from cranial nerves VII (''Facial n.''), IX (''Hypglossal n.''), and X (''Vagus n.'') via special visceral afferent (SVA) nerve fibres. A summary of their functions is as follows:

* ''Facial nerve n''. - carries taste information from the anterior 2/3 of the tongue.
* ''Hypoglossal n.'' - carries taste information from the posterior 1/3 of the tongue.
* ''Vagus n''. - carries taste information from the palate

'''Second order neurons''' - From the NTS second order neurons carry taste information to the Ventral posteromedial (VPM) nucleus in the thalamus.<ref name=PMID21885776/>

Copious scientific conjecture surrounds how each taste modality is transmitted to the brain. The ‘labelled-line’ hypothesis suggests that there are taste specific neurons which exclusively carry that taste modality to cortical areas. In analogous terms it can be viewed like the pipelines leading toward a house. Each pipeline carries its own utility, there is one for gas, another for water and finally for electricity with each terminating in slightly different areas of the house. In the same way, on the tongues there are different receptors for each taste which concurrently have individual nerve tracts leading to the primary gustatory cortex.

Contrapuntally there is electrophysiological evidence that single nerve afferents carry multiple modalities. These studies show one nerve afferent may have both a strong and a weak activation in response to a multiple taste stimuli.

===Cortical Areas===

[[Image:Primary gustatory cortex.png|thumb|Primary gustatory cortex]]

The location of the taste perception centres has been observed via functional magnetic resonance imaging (fMRI) studies. The primary taste cortex has been identified as being located in the anterior insula/frontal operculum (I/fO)<ref name=PMID22245354><pubmed>22245354</pubmed></ref>, with the secondary taste cortex in the caudolateral orbitofrontal cortex.<ref name=PMID21305668><pubmed>21305668</pubmed></ref> Within the insula there are further subdivisions related to each taste modality. Two photon calcium imaging research has outlined certain ’hot-spots’ of activation which are clearly delineated in relation to each taste. For example, the bitter modality is represented on the insula cortex approximately 1mm posterior to the middle cerebral artery whereas the sweet modality is represented 2.5mm rostrodorsal to the bitter field with no apparent overlap.<ref name=PMID21885776><pubmed>21885776</pubmed></ref> These findings lend weight to the idea that there is only one receptor for each taste quality.

It is interesting to note the relationship between taste and the reward centres of the brain. There is evidence of neural input to the ventral tegmental area (the origin of the mesolimbic dopaminergic reward pathway) and nucleus accumbens (involved in the conversion of motivation into physical action).<ref name=PMID21885776/> Neural connections such as this provide the foundations in explaining concepts such as flavour learning and preference. It may also give some insight into chronic problems such as food addiction and craving. As of yet however the gustatory neural network is not well understood and more research is required to elucidate the relationship between pleasure and taste sensation

==Timeline of Developmental Processes of the Gustatory System==

{| cellpadding=5 style="border:1px solid #BBB"
|- bgcolor="#89CFF0"
|'''Postovulatory Week'''||'''Description'''||'''Image'''
|- bgcolor="#BCD4E6"
|'''Week 6''' ||
The surface of the developing tongue is covered by nearly flat epitheliuem (Figure 1) <ref name=PMID9455607/>. The first gustatory papillae of the tongue appears in the caudal midline near the foramen caecum and the first circumvallate papilla develop on the dorsal midline <ref name=PMID9455607/> .
||
image
|- bgcolor="#89CFF0"
| '''Weeks 6 to 7'''||
Nerve fibres approach the basal lamina of lingual epithelium <ref name=PMID8955790><pubmed>8955790</pubmed></ref>. At this stage the lingual epithelium consists of two to three cell layers and there is not yet any sign of cell specializations indicating early taste bud formation<ref name=PMID8955790/>.
||
Image
|- bgcolor="#BCD4E6"
| '''Week 7 '''||
A series of epithelial swellings in the anterior part and midline of the tongue indicate early forming fungiform papillae (figure 2) <ref name=PMID9455607/>.
||
Image
|- bgcolor="#89CFF0"
| ''' Week 8 ''' ||
The lingual epithelium shows first signs of taste bud development as nerve fibres penetrate epithelial basal lamina <ref name=PMID8955790/> and form synapses with taste bud progenitor cells. The synapses reach a maximum around the 12th to 13th week <ref name=PMID8955790/>. However, at this time these cells are still poorly differentiated, elongated epithelial cells <ref name=PMID8955790/> . The synapses demonstrate the neuronal connection between the taste bud primordium and the central nervous system <ref name=PMID8955790/>. Ciliated cells also appear around the 8th week, however the significance of these cells which are scattered randomly across the lingual surface remains unclear <ref name=PMID8955790/>.
||
Image
|- bgcolor="#BCD4E6"
|''' Weeks 8-9''' ||
“By this stage the top surface of circumvallate papillae usually contains a taste pit partly filled with microvilli of presumed underlying taste bud cells” (Figure 10) <ref name=PMID9455607/>
||
Image
|- bgcolor="#89CFF0"
|''' Weeks 10-11''' ||
At this stage, the lingual epithelium compromises of about four cell layers, and the first shallow grooves above the taste bud primordium are developed <ref name=PMID8955790/>.

Fungiform papillae appear on the lateral margins and the tip of the tongue <ref name=PMID9455607/>, containing taste bud primordial that display the first signs of a primitive pore formation <ref name=PMID8955790/>.

Untypically differentiated apical cellular processes extend onto the surface <ref name=PMID9455607/>

Some taste bud primordial contain cells that perforate the covering epithelial later with short, broad untypically differentiated apical cellular processes. (Figure 3,4) <ref name=PMID8955790/> <ref name=PMID9455607/>
||
Image
|- bgcolor="#BCD4E6"
|''' Week 12 ''' ||
Taste bud cells are more clearly differentiated into epithelial cell types II and III <ref name=PMID8955790/>.
||
Image
|- bgcolor="#89CFF0"
|''' Weeks 12-13 ''' ||
By this stage the taste bud primordial are all located on the top of dermal papillae (Fig 6a) <ref name=PMID8955790/>. There is also maximum synapses between cells and afferent nerve fibres, which intermingle with each other to form a plexus-like structure <ref name=PMID8955790/>.
||
Image
|- bgcolor="#BCD4E6"
|''' Weeks 14 -15 ''' ||
The shape of the taste buds primordial begins to resemble those of adult taste buds <ref name=PMID8955790/>. By the 14th week the taste pores develop as the taste pits are filled by microvilli <ref name=PMID8955790/>, indicating the possibility that the taste buds begin their gustatory function <ref name=PMID8955790/>, however they still lack an electron-dense mucous material (Fig.10) <ref name=PMID8955790/>. The tastebuds only achieve a fully developed function in week 15 of gestation with the development of type I cells to produce the mucous material in the taste pit <ref name=PMID8955790/>.
||
Image
|}

==History of Discoveries==

{| cellpadding=5 style="border:1px solid #BBB"
|- bgcolor="#faecc8"
|''' Date'''|| '''Significant Discovery'''
|- bgcolor="#faf6ed"
|'''350BC'''
|| Aristotle writes about the basic tastes, sweet and bitter, which can be modified, he says, by salty and acidic.
|- bgcolor="#faecc8"
|'''1901'''
|| D. Hanig publishes a paper containing data of taste sensitivity in different regions of the tongue. The data are later misinterpreted, giving rise to the myth of the ‘tongue map’

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''1908'''
|Fifth basic taste discovered: savouriness, described as umami, which is conferred by glutamate.

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''1931'''
|Bitter taste sensitivity found to vary among humans (1)

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''1931-32'''
|Genetecists confirm findings about sensitivity to bitter tasting PTC and discover non-tasting is a recessive genetic trait (2,11)

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''1939'''
|Geneticists show that chimpansees like humans, vary in their ability to perceive the bitterness of PTC

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''1992'''
|Discovery of gustucin, a teste cell-specific G-protein, in the taste buds. Gustucin is later shown to mark bitter, umami and sweet cells (13)

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''1996'''
| Witt M and Reutter K of the Source Department of Anatomy, Technical University Dresden, Germany, carried out a transmission electron microscopy study to investigate the embryonic and fetal development of Human taste buds. Their results suggest an "at least dual function of embryonic/fetal taste buds", including non-gustatory, paracrine functions prior to the 14th week and gustatory after the 14th week. PMID 8955790

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''2000'''
|First taste sonsors, the T2R receptors, discovered (3)

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''2001'''
|The sweet receptor is discovered (5): a combination of TaR2 and T1R3.

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''2002'''
|Amino acid detector, T1R1 and T1R3 identified (6) = Umami

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''2005'''
|Sweet taste receptor found (15) in the GI tract

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''2006'''
|Cells for sour taste discovered, identified by PKD2L1 (4-7)

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''2007'''
|Harlow DE, Barlow LA of the Department of Cell and Developmental Biology, Rocky Mountain Taste and Smell Center, University of Colorado Denver Health Sciences Center provide evidence of the '''embryonic origin of gustatory cranial sensory neurons''' PMID 17826760

|- bgcolor="#faf6ed"
|style=white-space:nowrap|'''2009'''
|The Car4 receptor, which senses the carbon dioxide in fizzy drinks is found on sour cells (8)

A study by Hevezi P et al, presents the first comprehensive characterization of gene expression in primate taste buds, as opposed to previous studies which focused on rodents. PMID 19636377

|- bgcolor="#faecc8"
|style=white-space:nowrap|'''2010'''
|ENaC identified as the sodium-salt taste receptor (9)
|}

*[http://www.nature.com/nature/journal/v486/n7403_supp/fig_tab/486S2a_F1.html Gustatory system: The finer points of taste] <ref><pubmed>22717400</pubmed></ref>

==Adult Tongue and Taste Buds – Structure and Function==

'''Structure'''

The tongue is located on the floor of the oral cavity, It is a muscular structure with sensory units crowning. The tongue is divided into an anterior two thirds and a posterior one third. These regions are divided by a V-shaped groove at the back of the tongue (sulcus terminalis). The anterior two thirds of the tongue is covered by stratified squamous epithelium, It contains a roughened surface and has projections called papillae that vary in shape and number.

''''The Image Below is a very simplistic Diagram of the surface of the Tongue showing the locations of the different papillae and other important features'''

{|
| [[Image:Drawing of Tongue.png|500px]]

'''Papillae'''
[[File:Papillae.jpg|Left|thumb|200px|Close up of Human Tongue Papillae]]

There are 4 types of papillae on the tongue.
The most numerous papillae are the filiform papillae, which function to provide a surface that aids in holding food on the tongue during chewing but do not contain taste buds. The larger, less numerous fungiform papillae which contain taste buds, as do foliate papillae. Circumvallate papillae form a wide V at the sulcus terminalis also containing taste bus. There are no papillae or taste buds located on the posterior third of the tongue, having mucosal folds and the lingual tonsils instead.

'''Function'''

The tongue is for tasting, swallowing, and speech.
The functional unit of the taste bud is a taste cell, there are between 50 and 100 taste cells in each taste bud these taste cells represent all 5 different tastes. Historically is was believed that different areas of the tongue were responsible for different taste sensations although this has since been disregarded.[http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/W/Welcome.html] The papillae contain taste buds which are connected to the oral cavity via a taste pore, the function of the taste bud is to transmit a chemical signal from the oral cavity to a taste cell, this chemical signal is the converted into an electrical impulse and delivered to the brain via nerve fibres for interpretation.

'''The Image Below is a very simplistic Hand drawn Diagram of a taste bud, in an extreme close up, cross section view of the the taste bud unit, not to scale'''

[[File:Taste_bud_1.jpg]]

==Abnormalities==

===Knocking out P2X Receptors===

[[File:Image of taste being evoked by visualising ATP release.jpeg|Left|thumb|200px|Evoking taste - ATP release in tongue]]

Gustatory abnormalities has not been widely researched and what has been researched has been through animal testing, most commonly we have found on mice.

In Huang, 2008 this team used the release of the neurotransmitter, ATP (adenosine triphosphate) as a quantitative measurement of gustatory sensation and taste. This was done by using a comparison of wild type (WT) and double knockout (DKO) mice. P2X receptors, P2X2 and P2X3 were knocked out in the DKO mice. The premise of this article was that knocking out P2X receptors reduces transmitter secretion of ATP in taste buds, therefore they cannot taste.

It should be noted that the taste buds in DKO are functional, but are not stimulated by the administration of tastants.

The transmission of release of ATP is secretion through gap junction hemichannels (pannexin 1 gap junction).

When both P2X2 and P2X3 are knocked out, no taste is elicited. However they found that if either P2X2 OR P2X3 was knocked out there was a taste response. So the inference made from this is that if one of the two receptors from the P2X family was knocked out there still can have taste response. The WT mice showed significant stimulation by tastants whereas DKO had little to no stimulation of ATP release.<ref><pubmed>21940456</pubmed></ref>

===FGF signalling and genes===

Sprouty, or ''Srpy'', genes have been related to regulating the development of circumvillate papillae (CVP). The CVP are large dome shaped papillae, which form a 'V' just in front of the terminal sulcus.

By knocking out ''Spry'' genes using mice which had ''Spry1'' and ''Spry2'' knocked out showed that the number of CVP doubled. However, when Fibroblast Growth Factor gene ("Fgf10") was absent, the number of CVP was significantly reduced, if not completely absent. The correlation between ''Spry1/2'' and ''Fgf10'' is that ''Spry1/2'' antagonises "Fgf10" to limit the size of the CVP progenitor placode. Exclusive expression of ''Fgf10'' in the mesenchyme is necessary for the formation of CVP.

'''This image shows the CVP stained with H&E and scanned by Scanning Electron Microscope (SEM)'''
[[File:CVP of WT(top) and DKO(bottom) mice with H&E and SEM.png]]

'''This image shows the location of the CVP and the increased number in DKO mice by SEM'''
[[File:Mouse circumvallate papilla 01.jpg|300px]]

Taste buds develop from the mesenchyme but require local signalling to properly differentiate. Some signalling factors for proper development of taste buds besides FGF are: Sonic Hedgehog (SHH), Bone Morphogenetic Proteins (BMPs), Epidermal Growth Factor (EGF).

Additionally, this proves that the anterior and posterior developments of the tongue are derived from embryonic tissues, where the anterior tongue is derived from the ectoderm and the posterior tongue is derived from the endoderm. Taste buds develop from the mesenchyme but require local signalling to properly differentiate. Some signalling factors for proper development of taste buds besides FGF are: Sonic Hedgehog (SHH), Bone Morphogenetic Proteins (BMPs), Epidermal Growth Factor (EGF).

As mentioned above, this article shows that the anterior and posterior developments of the tongue are derived from embryonic tissues, where the anterior tongue is derived front the ectoderm and the posterior tongue is derived from the endoderm. Secondly, FGF is required to regulate the growth of taste buds, while ''Spry'' genes limit the number of CVP. ''Fgf10''& ''Spry 1&2''work antagonistically through receptor tyrosine kinase (RTK)signalling.

However, the deletion of ''Spry2''led to the increase of CVPs it should be noted that they found that a significant decrease in number of fungiform papillae. Contrastingly, the absence of ''Fgf10'', while leading to the absence of CVPs lead to an increase in number and size of fungiform papillae. Therefore these genes have different effects on the anterior and posterior developing tongue and taste buds.<ref><pubmed>21655085</pubmed></ref>

==Current Research==
We have an evolving understanding of Embryonic Taste development, through the use of state-of-the-art technology and research techniques we are able to make brilliant discoveries that continue to connect the dots of this amazing natural process of human development.
The majority of research in taste development is involving mice, these mammals show similar embryonic pathways to humans and research is performed in ethical and humane methods.

'''the below image shows histological stains of a mice tongue showing dysplasia"

[[File:Histology.jpg]]

'''Synergistic relationships of Six Genes '''

In an animal study using mice by Suzuki Y, Ikeda K, Kawakami K.(2011) Firstly nominating "Six Genes" as a major component in gustatory development, stating that deficiencies in certain Six genes (specifically Six1 & Six4) leads to poor development. Their research also highlights evidence of cooperative relationships between Six genes for normal advance. This experiment involved breeding mice containing exclusively Six1 and Six4 genes and examining the expression of these genes in papillae under high powered microscope observation. Understanding the role of certain genes along with the intrinsic relationships they hold is crucial for the ability to identify possible causes and correction of any abnormalities <ref><pubmed>21978088</pubmed></ref>

'''Neural Crest responsibilities '''

Another Animal Study involving mice explores a new idea of Neural crest (NC) contribution in taste development, specifically the development of papillae and taste buds. Liu HX, Komatsu Y, Mishina Y, Mistretta CM. (2012) suggest that Neural crest cells travel to the location of the tongue in early embryonic stages, gain epithelium phenotypes, multiply and then differentiate to eventually form taste papillae. The experiment involved the comparison of 2 different types of Cre line mice, which both express Cre gene in neural crest protocol, the different distribution patterns where observed in specific regions that NC is responsible for.<ref><pubmed>22659543</pubmed></ref>

'''Augmentation of Endoderm'''

In an animal study conducted by Rothova M, Thompson H, Lickert H, Tucker AS.(2012) exploring the historically debated issue of endoderm contribution to tongue development showed promising evidence that position of taste buds are patterned by the border of ectoderm and endoderm derivative epithelium. This study was accomplished via microscopic examination of previously stained specimens. Concluding endoderm has direct influence on gustatory develoment <ref><pubmed>22581563</pubmed></ref>

'''Changes in Taste Cells over time'''

Research by
Ozdener H, Spielman AI, Rawson NE.(2012) developing a culture which allows taste cells to survive for up to 12 months, empowers researchers to study the processes of proliferation, differentiation and function. This experiment will provide a precidnet for future study of taste cells, as these cells are able to operate and grow normally. <ref><pubmed>22643728</pubmed></ref>

'''Shh key component of taste bud proginators'''

A tamoxifen treatment which supresses Sonic hedgehog (Shh) secretion in mice proving to reduce the number of cells visable within papillae, in contrast mice not treated with tamoxifen showed a mark increase of cells within papillae, these cells are assumed to become taste cells in later development.
Specific mice were bred to trace the destination of taste placode cells, the study concluded that Shh expressing placodes are taste bud proginators which in turn become taste cells within taste buds although do not have any prescuros relationship with pappilae. The results were obtain by examination of mice embryos using Bright-field or multichannel fluorescent images through the use of an "Axiocam CCD camera and Axioplan fluorescence microscope with Axiovision software" a study by Harlow, Yang, Williams, Barlow (2011)<ref><pubmed>PMC2674259</pubmed></ref>

'''WNT family exhibit various roles'''

The WNT gene family has a function of signally proteins for various reason such as development, In 2010 Liu, Staubach Grosse, Walton, Saims, Gumucio, Mistretta explored recent findings on the role of WNT's in tongue and papillae development, Concluding that WNT/β-catenin is essential for fungiform papillae differing to WNT5a which proved to be principle in tongue development. Intrinsic chemical mediators were considered by manipulating a tissue culture and then throughaly examined by scanning photomicrograph. <ref><pubmed>PMC2768563</pubmed></ref>

'''The below image shows and example of tongue abnormalities, this is called "double tongue" each side has independent movement'''
[http://www.surgicalneurologyint.com/article.asp?issn=2152-7806;year=2012;volume=3;issue=1;spage=23;epage=23;aulast=Manjila]
[[File:Abnormal of tongue.jpg]]

==Useful links==

==Glossary==

ectoderm- outer germ layer of embryo

endoderm - inner germ layer of embryo

epithelium - basic animal tissue that is composed of tightly packed cells, usually covering the outer portion of organs

exocystosis - movement of contents out of cell

ganglia - the accumulation of a nerve cell body

growth factor - a substance that stimulates the growth of cells

gustatory - anything that relates to the taste sense

hydrolysis - breakdown of a chemical when it reacts with water

mesoderm - middle germ layer of embryo

mesenchyme - multipotential cells

neural crest - a part of the ectoderm found on both sides of the neural tube

neuron - most simplistic unit of the nervous system

neurotransmitter - chemicals which allow the passing of signals from neuron to neuron via connecting part (synapse)

papillae - small rough surface projection

six genes - a family of genes

Sonic hedgehog (Shh) - signalling protein invloved in normal development

sulcus terminalis - describes a physical transition point separating the anterior 2/3 of the tongue from the posterior 1/3

tamoxifen - hormonal altering drug

==Image gallery==

== References ==
<references/>

==External Links==
{{External Links}}

--[[User:Z8600021|Mark Hill]] 12:22, 15 August 2012 (EST) Please leave the content listed below the line at the bottom of your project page.

----

{{2012Projects}}

File:Taste qualities.gif

2012-09-25T12:05:33Z

Z3330986: /* Taste qualities */

2012-09-19T01:01:10Z

Z3330986: /* Cortical Areas */

=Taste Development=

==Gustatory System==

===Introduction===

[[Image:Taste qualities.gif|thumb|The five basic tastes]]

Taste or more appropriately gustation, is a fundamental survival tool in animals as it directs the consumption of essential nutrients. The five tastes that exist within the human gustatory system: salty, sweet, sour, bitter and umami, all signify basic physiological requirements. Salty tastes denote the presence of Na+, an important ion involved in the transportation and retention of water across cell membranes. Sweetness is the recognition of carbohydrates, essential for maintaining optimal brain function and providing the basis for energy production in muscle tissue via ATP hydrolysis. Similarly umami codes for the presence of L-amino acids, especially L-glutamate which is an integral component of protein synthesis.

These different modalities not only function to maintain the proper intake of nutrients within the body but also, by way of aversion, prohibit the consumption of undesired or poisonous materials. The bitter modality for example is generally regarded as displeasing to the human palate. It represents a high acid content which may be a result of foods which have become rotten or are inherently poisonous to the body.

Research has historically limited itself to investigating the mechanisms of these five taste qualities though it must be noted many other modalities may exist. Of particular conjecture is the existence of fatty acid recognition. In the past the detection of fat in food has been attributed to somatosensory inputs from the tongue, that is, the oily feel and texture of fat rather than its actual ‘taste’ allows the brain to encode for its presence. Further research is therefore required to elicit the precise mechanisms of fat detection.

===Cell Biology===

The five taste qualities are not all detected by the same type of receptor cell located within the taste bud. Like rods and cones in the eye which detect different wavelengths of light, there are specific types of receptors for different tastes. For example, sweet, umami and bitter are recognised by Type II G-protein coupled receptors, whereas sour is related to Type III presynaptic cells. The cell type involved in salty taste transduction is unknown however it is known that sodium ions can enter the receptor cell membrane via ion channel permeation.

====Type II receptors====

When a bitter, sweet or umami ligand binds to a type II G-coupled receptor, a cascade of chemical reactions causes the release of Ca2+ which in turn mediates exocystosis of ATP. The function of this ATP is threefold:

# Stimulates gustatory nerve afferents which project to gustatory nuclei in the spinal cord
# Excites Type III presynaptic nerve fibres to release serotonin.
# Has a positive feedback effect on type II receptor cells, increasing the level of ATP production.

The role of serotonin is believed to be in the form of lateral inhibition i.e. when a bitter quality is recognised, adjacent receptors for sweetness are deactivated and thus the two tastes may be clearly differentiated. It also has a negative feedback effect on receptor cells, inhibiting umami, bitter and sweet taste transduction.

==Taste Map==

[[File:Tongue map.jpg|left|thumb|197px|The traditional tongue map concept]]
The idea of a tongue map has disseminated through society for many years. This concept purports that different areas of the tongue are specialised to detect either sweet, salty, sour and bitter tastes. Recent research however has completely nullified such claims and suggests instead that different forms of taste are recognised all over the tongue as well as via the palate. Thus the term ''taste map'' has come to take on a new meaning and that is, the precise areas of taste modalities processing in areas of cortex and its subsequent neural inputs.

===Neural Pathways===

'''First order neurons''' - From the receptors located in the taste buds, gustatory nerve afferents project to the ipsilateral rostral 1/3 of the nucleus tractus solitarius (NTS), located in the medulla. This rostral 1/3 is commonly referred to as the ''gustatory nucleus''.

The ''gustatory nucleus'' receives input from cranial nerves VII (''Facial n.''), IX (''Hypglossal n.''), and X (''Vagus n.'') via special visceral afferent (SVA) nerve fibres. A summary of their functions is as follows:

* ''Facial nerve n''. - carries taste information from the anterior 2/3 of the tongue.
* ''Hypoglossal n.'' - carries taste information from the posterior 1/3 of the tongue.
* ''Vagus n''. - carries taste information from the palate

'''Second order neurons''' - From the NTS second order neurons carry taste information to the Ventral posteromedial (VPM) nucleus in the thalamus.

Copious scientific conjecture surrounds how each taste modality is transmitted to the brain. The ‘labelled-line’ hypothesis suggests that there are taste specific neurons which exclusively carry that taste modality to cortical areas. In analogous terms it can be viewed like the pipelines leading toward a house. Each pipeline carries its own utility, there is one for gas, another for water and finally for electricity with each terminating in slightly different areas of the house. In the same way, on the tongues there are different receptors for each taste which concurrently have individual nerve tracts leading to the primary gustatory cortex.

Contrapuntally there is electrophysiological evidence that single nerve afferents carry multiple modalities. These studies show one nerve afferent may have both a strong and a weak activation in response to a multiple taste stimuli.

===Cortical Areas===

[[Image:Primary gustatory cortex.png|thumb|Primary gustatory cortex]]

The location of the taste perception centres has been observed via functional magnetic resonance imaging (fMRI) studies. The primary taste cortex has been identified as being located in the anterior insula/frontal operculum (I/fO), with the secondary taste cortex in the caudolateral orbitofrontal cortex. Within the insula there are further subdivisions related to each taste modality. Two photon calcium imaging research has outlined certain ’hot-spots’ of activation which are clearly delineated in relation to each taste. For example, the bitter modality is represented on the insula cortex approximately 1mm posterior to the middle cerebral artery whereas the sweet modality is represented 2.5mm rostrodorsal to the bitter field with no apparent overlap.<ref name=PMID22245354><pubmed>22245354</pubmed></ref> These findings lend weight to the idea that there is only one receptor for each taste quality.

It is interesting to note the relationship between taste and the reward centres of the brain. There is evidence of neural input to the ventral tegmental area (the origin of the mesolimbic dopaminergic reward pathway) and nucleus accumbens (involved in the conversion of motivation into physical action). Neural connections such as this provide the foundations in explaining concepts such as flavour learning and preference. It may also give some insight into chronic problems such as food addiction and craving. As of yet however the gustatory neural network is not well understood and more research is required to elucidate the relationship between pleasure and taste sensation

==Timeline of Developmental Processes of the Gustatory System==

{| cellpadding=5 style="border:1px solid #BBB"
|- bgcolor="#89CFF0"
|'''Postovulatory Week'''||Description||Image
|- bgcolor="#BCD4E6"
|'''Week 6''' ||
The surface of the developing tongue is covered by nearly flat epitheliuem (Figure 1) <ref name="PMID9455607"><pubmed>9455607</pubmed></ref>. The first gustatory papillae of the tongue appears in the caudal midline near the foramen caecum <ref name=PMID9455607/> . On the dorsal midline the first circumvallate papilla develops (Figure 2) <ref name=PMID9455607/>
||
image
|- bgcolor="#89CFF0"
| '''Weeks 6 to 7'''||
Nerve fibres approach the basal lamina of lingual epithelium <ref name=PMID8955790><pubmed>8955790</pubmed></ref>. At this stage the lingual epithelium consists of two to three cell layers and there is not yet any sign of cell specializations indicating early taste bud formation<ref name=PMID8955790/>.
||
Image
|- bgcolor="#BCD4E6"
| '''Week 7 '''||
A series of epithelial swellings in the anterior part and midline of the tongue indicate early forming fungiform papillae (figure 2) <ref name=PMID9455607/>.
||
Image
|- bgcolor="#89CFF0"
| ''' Week 8 ''' ||
The lingual epithelium shows first signs of taste bud development as nerve fibres penetrate epithelial basal lamina <ref name=PMID8955790/> and form synapses with taste bud progenitor cells. The synapses reach a maximum around the 12th to 13th week <ref name=PMID8955790/>. However, at this time these cells are still poorly differentiated, elongated epithelial cells <ref name=PMID8955790/> . The synapses demonstrate the neuronal connection between the taste bud primordium and the central nervous system <ref name=PMID8955790/>. Ciliated cells also appear around the 8th week, however the significance of these cells which are scattered randomly across the lingual surface remains unclear <ref name=PMID8955790/>.
||
Image
|- bgcolor="#BCD4E6"
|''' Weeks 8-9''' ||
“By this stage the top surface of circumvallate papillae usually contains a taste pit partly filled with microvilli of presumed underlying taste bud cells” (Figure 10) <ref name=PMID9455607/>
||
Image
|- bgcolor="#89CFF0"
|''' Weeks 10-11''' ||
At this stage, the lingual epithelium compromises of about four cell layers, and the first shallow grooves above the taste bud primordium are developed <ref name=PMID8955790/>.

Fungiform papillae appear on the lateral margins and the tip of the tongue <ref name=PMID9455607/>, containing taste bud primordial that display the first signs of a primitive pore formation <ref name=PMID8955790/>.

Untypically differentiated apical cellular processes extend onto the surface <ref name=PMID9455607/>

Some taste bud primordial contain cells that perforate the covering epithelial later with short, broad untypically differentiated apical cellular processes. (Figure 3,4) <ref name=PMID8955790/> <ref name=PMID9455607/>
||
Image
|- bgcolor="#BCD4E6"
|''' Week 12 ''' ||
Taste bud cells are more clearly differentiated into epithelial cell types II and III <ref name=PMID8955790/>.
||
Image
|- bgcolor="#89CFF0"
|''' Weeks 12-13 ''' ||
By this stage the taste bud primordial are all located on the top of dermal papillae (Fig 6a) <ref name=PMID8955790/>. There is also maximum synapses between cells and afferent nerve fibres, which intermingle with each other to form a plexus-like structure <ref name=PMID8955790/>.
||
Image
|- bgcolor="#BCD4E6"
|''' Weeks 14 -15 ''' ||
The shape of the taste buds primordial begins to resemble those of adult taste buds <ref name=PMID8955790/>. By the 14th week the taste pores develop as the taste pits are filled by microvilli <ref name=PMID8955790/>, indicating the possibility that the taste buds begin their gustatory function <ref name=PMID8955790/>, however they still lack an electron-dense mucous material (Fig.10) <ref name=PMID8955790/>. The tastebuds only achieve a fully developed function in week 15 of gestation with the development of type I cells to produce the mucous material in the taste pit <ref name=PMID8955790/>.
||
Image
|}

*[http://embryology.med.unsw.edu.au/embryology/index.php?title=Sensory_-_Taste_Development Sensory Taste Development; UNSW Embryology]
*[http://www.ncbi.nlm.nih.gov/pubmed/8955790 Embryonic and early fetal development of human taste buds: a transmission electron microscopical study] <ref name=PMID8955790><pubmed>8955790</pubmed></ref> - Can't access full article!
*[http://www.ncbi.nlm.nih.gov/pubmed/9455607 Scanning electron microscopical studies of developing gustatory papillae in humans.] <ref><pubmed>9455607</pubmed></ref>
*[http://www.ncbi.nlm.nih.gov/pubmed/9541477 Innervation of developing human taste buds. An immunohistochemical study] <ref><pubmed>9541477</pubmed></ref>
*[http://www.ncbi.nlm.nih.gov/pubmed/8241557 Evidence for stimulus access to taste cells and nerves during development: an electron microscopic study.] <ref><pubmed>8241557</pubmed></ref>

==History of Discoveries==

{|"class=wikitable sortable" border="1"
|- bgcolor="#89CFF0"
! scope="col" | Date
! scope="col" | Significant Discovery
|- bgcolor="#BCD4E6"
|'''350BC'''
|Aristotle writes about the basic tastes, sweet and bitter, which can be modified, he says, by salty and acidic.
|-bgcolor="#89CFF0"
|style=white-space:nowrap|'''1901'''
|D. Hanig publishes a paper containing data of taste sensitivity in different regions of the tongue. The data are later misinterpreted, giving rise to the myth of the ‘tongue map’
|-bgcolor="#BCD4E6"
|style=white-space:nowrap|'''1908'''
|Fifth basic taste discovered: savouriness, described as umami, which is conferred by glutamate.
|-bgcolor="#89CFF0"
|style=white-space:nowrap|'''1931'''
|Bitter taste sensitivity found to vary among humans (1)
|-bgcolor="#BCD4E6"
|style=white-space:nowrap|'''1931-32'''
|Genetecists confirm findings about sensitivity to bitter tasting PTC and discover non-tasting is a recessive genetic trait (2,11)
|-bgcolor="#89CFF0"
|style=white-space:nowrap|'''1939'''
|Geneticists show that chimpansees like humans, vary in their ability to perceive the bitterness of PTC
|-bgcolor="#BCD4E6"
|style=white-space:nowrap|'''1992'''
|Discovery of gustucin, a teste cell-specific G-protein, in the taste buds. Gustucin is later shown to mark bitter, umami and sweet cells (13)
|-bgcolor="#89CFF0"
|style=white-space:nowrap|'''1992'''
|Discovery of gustucin, a teste cell-specific G-protein, in the taste buds. Gustucin is later shown to mark bitter, umami and sweet cells (13)
|-bgcolor="#BCD4E6"
|style=white-space:nowrap|'''1996'''
| Witt M and Reutter K of the Source Department of Anatomy, Technical University Dresden, Germany, carried out a transmission electron microscopy study to investigate the embryonic and fetal development of Human taste buds. Their results suggest an "at least dual function of embryonic/fetal taste buds", including non-gustatory, paracrine functions prior to the 14th week and gustatory after the 14th week. PMID 8955790
|-bgcolor="#89CFF0"
|style=white-space:nowrap|'''2000'''
|First taste sonsors, the T2R receptors, discovered (3)
|-bgcolor="#BCD4E6"
|style=white-space:nowrap|'''2001'''
|The sweet receptor is discovered (5): a combination of TaR2 and T1R3.
|-bgcolor="#89CFF0"
|style=white-space:nowrap|'''2002'''
|Amino acid detector, T1R1 and T1R3 identified (6) = Umami
|-bgcolor="#BCD4E6"
|style=white-space:nowrap|'''2005'''
|Sweet taste receptor found (15) in the GI tract
|-bgcolor="#89CFF0"
|style=white-space:nowrap|'''2006'''
|Cells for sour taste discovered, identified by PKD2L1 (4-7)
|-bgcolor="#BCD4E6"
|style=white-space:nowrap|'''2007'''
|Harlow DE, Barlow LA of the Department of Cell and Developmental Biology, Rocky Mountain Taste and Smell Center, University of Colorado Denver Health Sciences Center provide evidence of the '''embryonic origin of gustatory cranial sensory neurons''' PMID 17826760
|-bgcolor="#89CFF0"
|style=white-space:nowrap|'''2009'''
|The Car4 receptor, which senses the carbon dioxide in fizzy drinks is found on sour cells (8)

A study by Hevezi P et al, presents the first comprehensive characterization of gene expression in primate taste buds, as opposed to previous studies which focused on rodents. PMID 19636377
|-bgcolor="#BCD4E6"
|style=white-space:nowrap|'''2010'''
|ENaC identified as the sodium-salt taste receptor (9)
|}

*[http://www.nature.com/nature/journal/v486/n7403_supp/fig_tab/486S2a_F1.html Gustatory system: The finer points of taste] <ref><pubmed>22717400</pubmed></ref>

==Adult Tongue and Taste Buds – Structure and Function==

'''Structure'''

The tongue is located on the floor of the oral cavity, It is a muscular structure with sensory units crowning. The tongue is divided into an anterior two thirds and a posterior one third. These regions are divided by a V-shaped groove at the back of the tongue (sulcus terminalis). The anterior two thirds of the tongue is covered by stratified squamous epithelium, It contains a roughened surface and has projections called papillae that vary in shape and number.

''''The Image Below is a very simplistic Diagram of the surface of the Tongue showing the locations of the different papillae and other important features'''

{|
| [[Image:Drawing of Tongue.png|500px]]

'''Papillae'''
[[File:Papillae.jpg|Left|thumb|200px|Close up of Human Tongue Papillae]]

There are 4 types of papillae on the tongue.
The most numerous papillae are the filiform papillae, which function to provide a surface that aids in holding food on the tongue during chewing but do not contain taste buds. The larger, less numerous fungiform papillae which contain taste buds, as do foliate papillae. Circumvallate papillae form a wide V at the sulcus terminalis also containing taste bus. There are no papillae or taste buds located on the posterior third of the tongue, having mucosal folds and the lingual tonsils instead.

'''Function'''

The tongue is for tasting, swallowing, and speech.
The functional unit of the taste bud is a taste cell, there are between 50 and 100 taste cells in each taste bud these taste cells represent all 5 different tastes. Historically is was believed that different areas of the tongue were responsible for different taste sensations although this has since been disregarded.[http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/W/Welcome.html] The papillae contain taste buds which are connected to the oral cavity via a taste pore, the function of the taste bud is to transmit a chemical signal from the oral cavity to a taste cell, this chemical signal is the converted into an electrical impulse and delivered to the brain via nerve fibres for interpretation.

'''The Image Below is a very simplistic Hand drawn Diagram of a taste bud, in an extreme close up, cross section view of the the taste bud unit, not to scale'''

[[File:Taste_bud_1.jpg]]

==Abnormalities==

===Knocking out P2X Receptors===

Gustatory abnormalities has not been widely researched and what has been researched has been through animal testing, most commonly we have found on mice.

In Huang, 2008 this team used the release of the neurotransmitter, ATP (adenosine triphosphate) as a quantitative measurement of gustatory sensation and taste. This was done by using a comparison of wild type (WT) and double knockout (DKO) mice. P2X receptors, P2X2 and P2X3 were knocked out in the DKO mice. The premise of this article was that knocking out P2X receptors reduces transmitter secretion of ATP in taste buds, therefore they cannot taste.

It should be noted that the taste buds in DKO are functional, but are not stimulated by the administration of tastants.

The transmission of release of ATP is secretion through gap junction hemichannels (pannexin 1 gap junction).

When both P2X2 and P2X3 are knocked out, no taste is elicited. However they found that if either P2X2 OR P2X3 was knocked out there was a taste response. So the inference made from this is that if one of the two receptors from the P2X family was knocked out there still can have taste response. The WT mice showed significant stimulation by tastants whereas DKO had little to no stimulation of ATP release.<ref><pubmed>21940456</pubmed></ref>

[[Image:Image of taste being evoked by visualising ATP release.jpeg]]

===FGF signalling and genes===

Sprouty, or ''Srpy'', genes have been related to regulating the development of circumvillate papillae (CVP). The CVP are large dome shaped papillae, which form a 'V' just in front of the terminal sulcus.

By knocking out ''Spry'' genes using mice which had ''Spry1'' and ''Spry2'' knocked out showed that the number of CVP doubled. However, when Fibroblast Growth Factor gene ("Fgf10") was absent, the number of CVP was significantly reduced, if not completely absent. The correlation between ''Spry1/2'' and ''Fgf10'' is that ''Spry1/2'' antagonises "Fgf10" to limit the size of the CVP progenitor placode. Exclusive expression of ''Fgf10'' in the mesenchyme is necessary for the formation of CVP.

'''This image shows the CVP stained with H&E and scanned by Scanning Electron Microscope (SEM)'''
[[File:CVP of WT(top) and DKO(bottom) mice with H&E and SEM.png]]

'''This image shows the location of the CVP and the increased number in DKO mice by SEM'''
[[File:Mouse circumvallate papilla 01.jpg|300px]]

Taste buds develop from the mesenchyme but require local signalling to properly differentiate. Some signalling factors for proper development of taste buds besides FGF are: Sonic Hedgehog (SHH), Bone Morphogenetic Proteins (BMPs), Epidermal Growth Factor (EGF).

Additionally, this proves that the anterior and posterior developments of the tongue are derived from embryonic tissues, where the anterior tongue is derived from the ectoderm and the posterior tongue is derived from the endoderm. Taste buds develop from the mesenchyme but require local signalling to properly differentiate. Some signalling factors for proper development of taste buds besides FGF are: Sonic Hedgehog (SHH), Bone Morphogenetic Proteins (BMPs), Epidermal Growth Factor (EGF).

As mentioned above, this article shows that the anterior and posterior developments of the tongue are derived from embryonic tissues, where the anterior tongue is derived front the ectoderm and the posterior tongue is derived from the endoderm. Secondly, FGF is required to regulate the growth of taste buds, while ''Spry'' genes limit the number of CVP. ''Fgf10''& ''Spry 1&2''work antagonistically through receptor tyrosine kinase (RTK)signalling.

However, the deletion of ''Spry2''led to the increase of CVPs it should be noted that they found that a significant decrease in number of fungiform papillae. Contrastingly, the absence of ''Fgf10'', while leading to the absence of CVPs lead to an increase in number and size of fungiform papillae. Therefore these genes have different effects on the anterior and posterior developing tongue and taste buds.<ref><pubmed>21655085</pubmed></ref>

==Current Research==
We have an evolving understanding of Embryonic Taste development, through the use of state-of-the-art technology and research techniques we are able to make brilliant discoveries that continue to connect the dots of this amazing natural process of human development.
The majority of research in taste development is involving mice, these mammals show similar embryonic pathways to humans and research is performed in ethical and humane methods.

'''the below image shows histological stains of a mice tongue showing dysplasia"

[[File:Histology.jpg]]

'''Synergistic relationships of Six Genes '''

In an animal study using mice by Suzuki Y, Ikeda K, Kawakami K.(2011) Firstly nominating "Six Genes" as a major component in gustatory development, stating that deficiencies in certain Six genes (specifically Six1 & Six4) leads to poor development. Their research also highlights evidence of cooperative relationships between Six genes for normal advance. This experiment involved breeding mice containing exclusively Six1 and Six4 genes and examining the expression of these genes in papillae under high powered microscope observation. Understanding the role of certain genes along with the intrinsic relationships they hold is crucial for the ability to identify possible causes and correction of any abnormalities <ref><pubmed>21978088</pubmed></ref>

'''Neural Crest responsibilities '''

Another Animal Study involving mice explores a new idea of Neural crest (NC) contribution in taste development, specifically the development of papillae and taste buds. Liu HX, Komatsu Y, Mishina Y, Mistretta CM. (2012) suggest that Neural crest cells travel to the location of the tongue in early embryonic stages, gain epithelium phenotypes, multiply and then differentiate to eventually form taste papillae. The experiment involved the comparison of 2 different types of Cre line mice, which both express Cre gene in neural crest protocol, the different distribution patterns where observed in specific regions that NC is responsible for.<ref><pubmed>22659543</pubmed></ref>

'''Augmentation of Endoderm'''

In an animal study conducted by Rothova M, Thompson H, Lickert H, Tucker AS.(2012) exploring the historically debated issue of endoderm contribution to tongue development showed promising evidence that position of taste buds are patterned by the border of ectoderm and endoderm derivative epithelium. This study was accomplished via microscopic examination of previously stained specimens. Concluding endoderm has direct influence on gustatory develoment <ref><pubmed>22581563</pubmed></ref>

'''Changes in Taste Cells over time'''

Research by
Ozdener H, Spielman AI, Rawson NE.(2012) developing a culture which allows taste cells to survive for up to 12 months, empowers researchers to study the processes of proliferation, differentiation and function. This experiment will provide a precidnet for future study of taste cells, as these cells are able to operate and grow normally. <ref><pubmed>22643728</pubmed></ref>

'''Character of BDNF'''

Brain-derived neurotrophic factor (BDNF) was identified to promote gustatory neuron development, along with identifying the embryonic precursor populations for cranial ganglia in mice through the use of fate mapping in a study by Harlow, Yang, Williams, Barlow (2011)<ref><pubmed>PMC2674259</pubmed></ref>

'''WNT family exhibit various roles'''

The WNT gene family has a function of signally proteins for various reason such as development, In 2010 Liu, Staubach Grosse, Walton, Saims, Gumucio, Mistretta explored recent findings on the role of WNT's in tongue and papillae development, Concluding that WNT/β-catenin is essential for fungiform papillae differing to WNT5a which proved to be principle in tongue development. Intrinsic chemical mediators were considered by manipulating a tissue culture and then throughaly examined by scanning photomicrograph. <ref><pubmed>PMC2768563</pubmed></ref>

'''The below image shows and example of tongue abnormalities, this is called "double tongue" each side has independent movement'''
[http://www.surgicalneurologyint.com/article.asp?issn=2152-7806;year=2012;volume=3;issue=1;spage=23;epage=23;aulast=Manjila]
[[File:Abnormal of tongue.jpg]]

==Useful links==

==Glossary==

ectoderm- outer germ layer of embryo

endoderm - inner germ layer of embryo

epithelium - basic animal tissue that is composed of tightly packed cells, usually covering the outer portion of organs

exocystosis - movement of contents out of cell

ganglia - the accumulation of a nerve cell body

growth factor - a substance that stimulates the growth of cells

gustatory - anything that relates to the taste sense

hydrolysis - breakdown of a chemical when it reacts with water

mesoderm - middle germ layer of embryo

mesenchyme - multipotential cells

neural crest - a part of the ectoderm found on both sides of the neural tube

neuron - most simplistic unit of the nervous system

neurotransmitter - chemicals which allow the passing of signals from neuron to neuron via connecting part (synapse)

papillae - small rough surface projection

six genes - a family of genes

sulcus terminalis - describes a physical transition point separating the anterior 2/3 of the tongue from the posterior 1/3

==Image gallery==

== References ==
<references/>

==External Links==
{{External Links}}

--[[User:Z8600021|Mark Hill]] 12:22, 15 August 2012 (EST) Please leave the content listed below the line at the bottom of your project page.

----

{{2012Projects}}

2012-09-18T14:55:38Z

Z3330986: /* Cell Biology */

=Taste Development=

==Gustatory System==

===Introduction===

[[Image:Taste qualities.gif|thumb|The five basic tastes]]

Taste or more appropriately gustation, is a fundamental survival tool in animals as it directs the consumption of essential nutrients. The five tastes that exist within the human gustatory system: salty, sweet, sour, bitter and umami, all signify basic physiological requirements. Salty tastes denote the presence of Na+, an important ion involved in the transportation and retention of water across cell membranes. Sweetness is the recognition of carbohydrates, essential for maintaining optimal brain function and providing the basis for energy production in muscle tissue via ATP hydrolysis. Similarly umami is codes for the presence of L-amino acids, especially L-glutamate which is an integral component of protein systhesis.

These different modalities not only function to maintain the proper intake of nutrients within the body but also, by way of aversion, prohibit the consumption of undesired or poisonous materials. The bitter modality for example is generally regarded as displeasing to the human palate. It represents a high acid content which may be a result of foods which have become rotten or are inherently poisonous to the body.

Research has historically limited itself to investigating the mechanisms of these five taste qualities though it must be noted many other modalities may exist. Of particular conjecture is the existence of fatty acid recognition. In the past the detection of fat in food has been attributed to somatosensory inputs from the tongue, that is, the oily feel and texture of fat rather than its actual ‘taste’ allows the brain to encode for its presence. Further research is therefore required to elicit the precise mechanisms of fat detection.

===Cell Biology===

The five taste qualities are not all detected by the same type of receptor cell located within the taste bud. Like rods and cones in the eye which detect different wavelengths of light, there are specific types of receptors for different tastes. For example, sweet, umami and bitter are recognised by Type II G-protein coupled receptors, whereas sour is related to Type III presynaptic cells. The cell type involved in salty taste transduction is unknown however it is known that sodium ions can enter the receptor cell membrane via ion channel permeation.

====Type II receptors====

When a bitter, sweet or umami ligand binds to a type II G-coupled receptor, a cascade of chemical reactions causes the release of Ca2+ which in turn mediates exocystosis of ATP. The function of this ATP is threefold:

# Stimulates gustatory nerve afferents which project to gustatory nuclei in the spinal cord
# Excites Type III presynaptic nerve fibres to release serotonin.
# Has a positive feedback effect on type II receptor cells, increasing the level of ATP production.

The role of serotonin is believed to be in the form of lateral inhibition i.e. when a bitter quality is recognised, adjacent receptors for sweetness are deactivated and thus the two tastes may be clearly differentiated. It also has a negative feedback effect on receptor cells, inhibiting umami, bitter and sweet taste transduction.

==Timeline of Developmental Processes of the Gustatory System==

{| cellpadding=5 style="border:1px solid #BBB"
|- bgcolor="#89CFF0"
|'''Postovulatory Week'''||Description||Image
|- bgcolor="#BCD4E6"
|'''Week 6''' ||
The surface of the developing tongue is covered by nearly flat epitheliuem (Figure 1) <ref name="PMID9455607"><pubmed>9455607</pubmed></ref>. The first gustatory papillae of the tongue appears in the caudal midline near the foramen caecum <ref name=PMID9455607/> . On the dorsal midline the first circumvallate papilla develops (Figure 2) <ref name=PMID9455607/>
||
image
|- bgcolor="#89CFF0"
| '''Weeks 6 to 7'''||
Nerve fibres approach the basal lamina of lingual epithelium <ref name=PMID8955790><pubmed>8955790</pubmed></ref>. At this stage the lingual epithelium consists of two to three cell layers and there is not yet any sign of cell specializations indicating early taste bud formation<ref name=PMID8955790/>.
||
Image
|- bgcolor="#BCD4E6"
| '''Week 7 '''||
A series of epithelial swellings in the anterior part and midline of the tongue indicate early forming fungiform papillae (figure 2) <ref name=PMID9455607/>.
||
Image
|- bgcolor="#89CFF0"
| ''' Week 8 ''' ||
The lingual epithelium shows first signs of taste bud development as nerve fibres penetrate epithelial basal lamina <ref name=PMID8955790/> and form synapses with taste bud progenitor cells. The synapses reach a maximum around the 12th to 13th week <ref name=PMID8955790/>. However, at this time these cells are still poorly differentiated, elongated epithelial cells <ref name=PMID8955790/> . The synapses demonstrate the neuronal connection between the taste bud primordium and the central nervous system <ref name=PMID8955790/>. Ciliated cells also appear around the 8th week, however the significance of these cells which are scattered randomly across the lingual surface remains unclear <ref name=PMID8955790/>.
||
Image
|- bgcolor="#BCD4E6"
|''' Weeks 8-9''' ||
“By this stage the top surface of circumvallate papillae usually contains a taste pit partly filled with microvilli of presumed underlying taste bud cells” (Figure 10) <ref name=PMID9455607/>
||
Image
|- bgcolor="#89CFF0"
|''' Weeks 10-11''' ||
At this stage, the lingual epithelium compromises of about four cell layers, and the first shallow grooves above the taste bud primordium are developed <ref name=PMID8955790/>.

Fungiform papillae appear on the lateral margins and the tip of the tongue <ref name=PMID9455607/>, containing taste bud primordial that display the first signs of a primitive pore formation <ref name=PMID8955790/>.

Untypically differentiated apical cellular processes extend onto the surface <ref name=PMID9455607/>

Some taste bud primordial contain cells that perforate the covering epithelial later with short, broad untypically differentiated apical cellular processes. (Figure 3,4) <ref name=PMID8955790/> <ref name=PMID9455607/>
||
Image
|- bgcolor="#BCD4E6"
|''' Week 12 ''' ||
Taste bud cells are more clearly differentiated into epithelial cell types II and III <ref name=PMID8955790/>.
||
Image
|- bgcolor="#89CFF0"
|''' Weeks 12-13 ''' ||
By this stage the taste bud primordial are all located on the top of dermal papillae (Fig 6a) <ref name=PMID8955790/>. There is also maximum synapses between cells and afferent nerve fibres, which intermingle with each other to form a plexus-like structure <ref name=PMID8955790/>.
||
Image
|- bgcolor="#BCD4E6"
|''' Weeks 14 -15 ''' ||
The shape of the taste buds primordial begins to resemble those of adult taste buds <ref name=PMID8955790/>. By the 14th week the taste pores develop as the taste pits are filled by microvilli <ref name=PMID8955790/>, indicating the possibility that the taste buds begin their gustatory function <ref name=PMID8955790/>, however they still lack an electron-dense mucous material (Fig.10) <ref name=PMID8955790/>. The tastebuds only achieve a fully developed function in week 15 of gestation with the development of type I cells to produce the mucous material in the taste pit <ref name=PMID8955790/>.
||
Image
|}

*[http://embryology.med.unsw.edu.au/embryology/index.php?title=Sensory_-_Taste_Development Sensory Taste Development; UNSW Embryology]
*[http://www.ncbi.nlm.nih.gov/pubmed/8955790 Embryonic and early fetal development of human taste buds: a transmission electron microscopical study] <ref name=PMID8955790><pubmed>8955790</pubmed></ref> - Can't access full article!
*[http://www.ncbi.nlm.nih.gov/pubmed/9455607 Scanning electron microscopical studies of developing gustatory papillae in humans.] <ref><pubmed>9455607</pubmed></ref>
*[http://www.ncbi.nlm.nih.gov/pubmed/9541477 Innervation of developing human taste buds. An immunohistochemical study] <ref><pubmed>9541477</pubmed></ref>
*[http://www.ncbi.nlm.nih.gov/pubmed/8241557 Evidence for stimulus access to taste cells and nerves during development: an electron microscopic study.] <ref><pubmed>8241557</pubmed></ref>

==History of Discoveries==

{|"class=wikitable sortable" border="1"
|- bgcolor="#89CFF0"
! scope="col" | Date
! scope="col" | Significant Discovery
|- bgcolor="#BCD4E6"
|'''350BC'''
|Aristotle writes about the basic tastes, sweet and bitter, which can be modified, he says, by salty and acidic.
|-bgcolor="#89CFF0"
|style=white-space:nowrap|'''1901'''
|D. Hanig publishes a paper containing data of taste sensitivity in different regions of the tongue. The data are later misinterpreted, giving rise to the myth of the ‘tongue map’
|-bgcolor="#BCD4E6"
|style=white-space:nowrap|'''1908'''
|Fifth basic taste discovered: savouriness, described as umami, which is conferred by glutamate.
|-bgcolor="#89CFF0"
|style=white-space:nowrap|'''1931'''
|Bitter taste sensitivity found to vary among humans (1)
|-bgcolor="#BCD4E6"
|style=white-space:nowrap|'''1931-32'''
|Genetecists confirm findings about sensitivity to bitter tasting PTC and discover non-tasting is a recessive genetic trait (2,11)
|-bgcolor="#89CFF0"
|style=white-space:nowrap|'''1939'''
|Geneticists show that chimpansees like humans, vary in their ability to perceive the bitterness of PTC
|-bgcolor="#BCD4E6"
|style=white-space:nowrap|'''1992'''
|Discovery of gustucin, a teste cell-specific G-protein, in the taste buds. Gustucin is later shown to mark bitter, umami and sweet cells (13)
|-bgcolor="#89CFF0"
|style=white-space:nowrap|'''1992'''
|Discovery of gustucin, a teste cell-specific G-protein, in the taste buds. Gustucin is later shown to mark bitter, umami and sweet cells (13)
|-bgcolor="#BCD4E6"
|style=white-space:nowrap|'''1996'''
| Witt M and Reutter K of the Source Department of Anatomy, Technical University Dresden, Germany, carried out a transmission electron microscopy study to investigate the embryonic and fetal development of Human taste buds. Their results suggest an "at least dual function of embryonic/fetal taste buds", including non-gustatory, paracrine functions prior to the 14th week and gustatory after the 14th week. PMID 8955790
|-bgcolor="#89CFF0"
|style=white-space:nowrap|'''2000'''
|First taste sonsors, the T2R receptors, discovered (3)
|-bgcolor="#BCD4E6"
|style=white-space:nowrap|'''2001'''
|The sweet receptor is discovered (5): a combination of TaR2 and T1R3.
|-bgcolor="#89CFF0"
|style=white-space:nowrap|'''2002'''
|Amino acid detector, T1R1 and T1R3 identified (6) = Umami
|-bgcolor="#BCD4E6"
|style=white-space:nowrap|'''2005'''
|Sweet taste receptor found (15) in the GI tract
|-bgcolor="#89CFF0"
|style=white-space:nowrap|'''2006'''
|Cells for sour taste discovered, identified by PKD2L1 (4-7)
|-bgcolor="#BCD4E6"
|style=white-space:nowrap|'''2007'''
|Harlow DE, Barlow LA of the Department of Cell and Developmental Biology, Rocky Mountain Taste and Smell Center, University of Colorado Denver Health Sciences Center provide evidence of the '''embryonic origin of gustatory cranial sensory neurons''' PMID 17826760
|-bgcolor="#89CFF0"
|style=white-space:nowrap|'''2009'''
|The Car4 receptor, which senses the carbon dioxide in fizzy drinks is found on sour cells (8)

A study by Hevezi P et al, presents the first comprehensive characterization of gene expression in primate taste buds, as opposed to previous studies which focused on rodents. PMID 19636377
|-bgcolor="#BCD4E6"
|style=white-space:nowrap|'''2010'''
|ENaC identified as the sodium-salt taste receptor (9)
|}

*[http://www.nature.com/nature/journal/v486/n7403_supp/fig_tab/486S2a_F1.html Gustatory system: The finer points of taste] <ref><pubmed>22717400</pubmed></ref>

==Adult Tongue and Taste Buds – Structure and Function==

The tongue is for tasting, swallowing, and speech.The tongue is located on the floor of the oral cavity, It is a muscular structure with sensory units crowning. The tongue is divided into an anterior two thirds and a posterior one third. These regions are divided by a V-shaped groove at the back of the tongue (sulcus terminalis). The anterior two thirds of the tongue is covered by stratified squamous epithelium, It contains a roughened surface and has projections called papillae that vary in shape and number. The most numerous papillae are the filiform papillae, which function to provide a surface that aids in holding food on the tongue during chewing. The larger, less numerous fungiform papillae are scattered among the filiform papillae where as the Circumvallate papilae form a wide V at the sulcus terminalis. There are no papillae or taste buds located on the posterior third of the tongue, having mucosal folds and the lingual tonsils instead.

'''The Image Below is a very simplistic Hand drawn Diagram of the surface of the Tongue showing the locations of the different papillae & and also the sulcus terminalis, This image indicates the tongue from an above veiw'''

{|
| [[Image:Drawing of Tongue.png|500px]]

The functional unit of the taste bud is a taste cells, there are between 50 and 100 taste cells in each taste bud these taste cells represent all 5 different tastes. Historically is was believed that different areas of the tongue were responsible for different taste sensations although this has since been disregarded.[http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/W/Welcome.html] The papillae contain taste buds which are connected to the oral cavity via a taste pore, the function of the taste bud is to transmit a chemical signal from the oral cavity to a taste cell, this chemical signal is the converted into an electrical impulse and delivered to the brain via nerve fibres for interpretation.

'''The Image Below is a very simplistic Hand drawn Diagram of a taste bud, in an extreme close up, cross section view of the the taste bud unit, not to scale'''

[[File:Taste_bud_1.jpg]]

==Taste Map==

==Abnormalities==
(try to include technologies to detect abnormalities during pregnancy)

===Knocking out P2X Receptors===

Gustatory abnormalities has not been widely researched and what has been researched has been through animal testing, most commonly we have found on mice.

In Huang, 2008 [PMID:21940456] this team used the release of the neurotransmitter, ATP (adenosine triphosphate) as a quantitative measurement of gustatory sensation and taste. This was done by using a comparison of wild type (WT) and double knockout (DKO) mice. P2X receptors, P2X2 and P2X3 were knocked out in the DKO mice. The premise of this article was that knocking out P2X receptors reduces transmitter secretion of ATP in taste buds, therefore they cannot taste.

It should be noted that the taste buds in DKO are functional, but are not stimulated by the administration of tastants.

The transmission of release of ATP is secretion through gap junction hemichannels (pannexin 1 gap junction).

When both P2X2 and P2X3 are knocked out, no taste is elicited. However they found that if either P2X2 OR P2X3 was knocked out there was a taste response. So the inference made from this is that if one of the two receptors from the P2X family was knocked out there still can have taste response. The WT mice showed significant stimulation by tastants whereas DKO had little to no stimulation of ATP release.

'''Insert image 4 from article here'''

===FGF signalling and genes===

Sprouty, or ''Srpy'', genes have been related to regulating the development of circumvillate papillae (CVP). The CVP are large dome shaped papillae, which form a 'V' just in front of the terminal sulcus.

By knocking out ''Spry'' genes using mice which had ''Spry1'' and ''Spry2'' knocked out showed that the number of CVP doubled. However, when Fibroblast Growth Factor gene ("Fgf10") was absent, the number of CVP was significantly reduced, if not completely absent. The correlation between ''Spry1/2'' and ''Fgf10'' is that ''Spry1/2'' antagonises "Fgf10" to limit the size of the CVP progenitor placode. Exclusive expression of ''Fgf10'' in the mesenchyme is necessary for the formation of CVP.

'''This image shows the CVP stained with H&E and scanned by Scanning Electron Microscope (SEM)'''
[[File:CVP of WT(top) and DKO(bottom) mice with H&E and SEM.png]]

Taste buds develop from the mesenchyme but require local signalling to properly differentiate. Some signalling factors for proper development of taste buds besides FGF are: Sonic Hedgehog (SHH), Bone Morphogenetic Proteins (BMPs), Epidermal Growth Factor (EGF).

Additionally, this proves that the anterior and posterior developments of the tongue are derived from embryonic tissues, where the anterior tongue is derived fromt he ectoderm and the posterior tongue is derived from the endoderm.

==Current Research==
We have an evolving understanding of Embryonic Taste development, through the use of state-of-the-art technology and research techniques we are able to make brilliant discoveries that continue to connect the dots of this amazing natural process of human development.
The majority of research in taste development is involving mice, these mammals show similar embryonic pathways to humans and research is performed in ethical and humane methods.

'''the below image shows histological stains of a mice tongue'''

[[File:Histology.jpg]]

In an animal study using mice by Suzuki Y, Ikeda K, Kawakami K.(2011) Firstly nominating "Six Genes" as a major component in gustatory development, stating that deficiencies in certain Six genes (specifically Six1 & Six4) leads to poor development. Their research also highlights evidence of cooperative relationships between Six genes for normal advance. Understanding the role of certain genes along with the intrinsic relationships they hold is crucial for the ability to identify possible causes and correction of any abnormalities <ref><pubmed>21978088</pubmed></ref>
Another Animal Study involving mice explores a new idea of Neural crest contribution in taste development, specifically the development of papillae and taste buds. Liu HX, Komatsu Y, Mishina Y, Mistretta CM. (2012) suggest that Neural crest cells travel to the location of the tongue in early embryonic stages, gain epithelium phenotypes, multiply and then differentiate to eventually form taste papillae. Appreciating embryonic courses allows constant monitoring throughout expansion of the foetus.<ref><pubmed>22659543</pubmed></ref>
In an animal study conducted by Rothova M, Thompson H, Lickert H, Tucker AS.(2012) exploring the historically debated issue of endoderm contribution to tongue development showed promising evidence that position of taste buds are patterned by the border of ectoderm and endoderm derivative epithelium. <ref><pubmed>ref>22581563</pubmed></ref> Research by Ozdener H, Spielman AI, Rawson NE.(2012) developing a culture which allows taste cells to survive for up to 12 months, empowers researchers to study the processes of proliferation, differentiation and function. <ref><pubmed>ref>22643728</pubmed></ref>
Brain-derived neurotrophic factor (BDNF) was identified to promote gustatory neuron development, along with identifying the embryonic precursor populations for cranial ganglia in mice through the use of fate mapping in a study by Harlow, Yang, Williams, Barlow (2011)<ref><pubmed>ref>PMC2674259</pubmed></ref>
The WNT gene family has a function of signally proteins for various reason such as development, In 2010 Liu, Staubach Grosse, Walton, Saims, Gumucio, Mistretta explored recent findings on the role of WNT's in tongue and papillae development, Concluding that WNT/β-catenin is essential for fungiform papillae differing to WNT5a which proved to be principle in tongue development. <ref><pubmed>ref>PMC2768563</pubmed></ref>

'''The below image shows and example of tongue abnormalities, this is called "double tongue" each side has independent movement'''
[http://www.surgicalneurologyint.com/article.asp?issn=2152-7806;year=2012;volume=3;issue=1;spage=23;epage=23;aulast=Manjila]
[[File:Abnormal of tongue.jpg]]

==Useful links==

==Glossary==

==Image gallery==

== References ==
<references/>

==Glossary==

==External Links==
{{External Links}}

--[[User:Z8600021|Mark Hill]] 12:22, 15 August 2012 (EST) Please leave the content listed below the line at the bottom of your project page.

----

{{2012Projects}}

2012 Group Project 3

2012-09-18T14:15:57Z

Z3330986: /* Introduction */

File:Taste qualities.gif

2012-09-18T14:12:19Z

Z3330986: ==Taste qualities== Taste qualities, the taste receptors that detect them, and examples of natural stimuli. Five recognized taste qualities—sweet, sour, bitter, salty, and umami—are detected by taste buds. Bitter taste is thought to protect against in

2012 Group Project 3

2012-09-18T14:05:19Z

Z3330986: /* Introduction to the Gustatory System */

=Taste Development=

==Gustatory System==

===Introduction===

Taste or more appropriately gustation, is a fundamental survival tool in animals as it directs the consumption of essential nutrients. The five tastes that exist within the human gustatory system: salty, sweet, sour, bitter and umami, all signify basic physiological requirements. Salty tastes denote the presence of Na+, an important ion involved in the transportation and retention of water across cell membranes. Sweetness is the recognition of carbohydrates, essential for maintaining optimal brain function and providing the basis for energy production in muscle tissue via ATP hydrolysis. Similarly umami is codes for the presence of L-amino acids, especially L-glutamate which is an integral component of protein systhesis.

These different modalities not only function to maintain the proper intake of nutrients within the body but also, by way of aversion, prohibit the consumption of undesired or poisonous materials. The bitter modality for example is generally regarded as displeasing to the human palate. It represents a high acid content which may be a result of foods which have become rotten or are inherently poisonous to the body.

Research has historically limited itself to investigating the mechanisms of these five taste qualities though it must be noted many other modalities may exist. Of particular conjecture is the existence of fatty acid recognition. In the past the detection of fat in food has been attributed to somatosensory inputs from the tongue, that is, the oily feel and texture of fat rather than its actual ‘taste’ allows the brain to encode for its presence. Further research is therefore required to elicit the precise mechanisms of fat detection.

===Cell Biology===

==Timeline of Developmental Processes of the Gustatory System==

{| cellpadding=5 style="border:1px solid #BBB"
|- bgcolor="#89CFF0"
|'''Postovulatory Week'''||Description||Image
|- bgcolor="#BCD4E6"
|'''Week 6''' ||
The surface of the developing tongue is covered by nearly flat epitheliuem (Figure 1) <ref name="PMID9455607"><pubmed>9455607</pubmed></ref>. The first gustatory papillae of the tongue appears in the caudal midline near the foramen caecum <ref name=PMID9455607/> . On the dorsal midline the first circumvallate papilla develops (Figure 2) <ref name=PMID9455607/>
||
image
|- bgcolor="#89CFF0"
| '''Weeks 6 to 7'''||
Nerve fibres approach the basal lamina of lingual epithelium <ref name=PMID8955790><pubmed>8955790</pubmed></ref>. At this stage the lingual epithelium consists of two to three cell layers and there is not yet any sign of cell specializations indicating early taste bud formation<ref name=PMID8955790/>.
||
Image
|- bgcolor="#BCD4E6"
| '''Week 7 '''||
A series of epithelial swellings in the anterior part and midline of the tongue indicate early forming fungiform papillae (figure 2) <ref name=PMID9455607/>.
||
Image
|- bgcolor="#89CFF0"
| ''' Week 8 ''' ||
The lingual epithelium shows first signs of taste bud development as nerve fibres penetrate epithelial basal lamina <ref name=PMID8955790/> and form synapses with taste bud progenitor cells. The synapses reach a maximum around the 12th to 13th week <ref name=PMID8955790/>. However, at this time these cells are still poorly differentiated, elongated epithelial cells <ref name=PMID8955790/> . The synapses demonstrate the neuronal connection between the taste bud primordium and the central nervous system <ref name=PMID8955790/>. Ciliated cells also appear around the 8th week, however the significance of these cells which are scattered randomly across the lingual surface remains unclear <ref name=PMID8955790/>.
||
Image
|- bgcolor="#BCD4E6"
|''' Weeks 8-9''' ||
“By this stage the top surface of circumvallate papillae usually contains a taste pit partly filled with microvilli of presumed underlying taste bud cells” (Figure 10) <ref name=PMID9455607/>
||
Image
|- bgcolor="#89CFF0"
|''' Weeks 10-11''' ||
At this stage, the lingual epithelium compromises of about four cell layers, and the first shallow grooves above the taste bud primordium are developed <ref name=PMID8955790/>.

Fungiform papillae appear on the lateral margins and the tip of the tongue <ref name=PMID9455607/>, containing taste bud primordial that display the first signs of a primitive pore formation <ref name=PMID8955790/>.

Untypically differentiated apical cellular processes extend onto the surface <ref name=PMID9455607/>

Some taste bud primordial contain cells that perforate the covering epithelial later with short, broad untypically differentiated apical cellular processes. (Figure 3,4) <ref name=PMID8955790/> <ref name=PMID9455607/>
||
Image
|- bgcolor="#BCD4E6"
|''' Week 12 ''' ||
Taste bud cells are more clearly differentiated into epithelial cell types II and III <ref name=PMID8955790/>.
||
Image
|- bgcolor="#89CFF0"
|''' Weeks 12-13 ''' ||
By this stage the taste bud primordial are all located on the top of dermal papillae (Fig 6a) <ref name=PMID8955790/>. There is also maximum synapses between cells and afferent nerve fibres, which intermingle with each other to form a plexus-like structure <ref name=PMID8955790/>.
||
Image
|- bgcolor="#BCD4E6"
|''' Weeks 14 -15 ''' ||
The shape of the taste buds primordial begins to resemble those of adult taste buds <ref name=PMID8955790/>. By the 14th week the taste pores develop as the taste pits are filled by microvilli <ref name=PMID8955790/>, indicating the possibility that the taste buds begin their gustatory function <ref name=PMID8955790/>, however they still lack an electron-dense mucous material (Fig.10) <ref name=PMID8955790/>. The tastebuds only achieve a fully developed function in week 15 of gestation with the development of type I cells to produce the mucous material in the taste pit <ref name=PMID8955790/>.
||
Image
|}

*[http://embryology.med.unsw.edu.au/embryology/index.php?title=Sensory_-_Taste_Development Sensory Taste Development; UNSW Embryology]
*[http://www.ncbi.nlm.nih.gov/pubmed/8955790 Embryonic and early fetal development of human taste buds: a transmission electron microscopical study] <ref name=PMID8955790><pubmed>8955790</pubmed></ref> - Can't access full article!
*[http://www.ncbi.nlm.nih.gov/pubmed/9455607 Scanning electron microscopical studies of developing gustatory papillae in humans.] <ref><pubmed>9455607</pubmed></ref>
*[http://www.ncbi.nlm.nih.gov/pubmed/9541477 Innervation of developing human taste buds. An immunohistochemical study] <ref><pubmed>9541477</pubmed></ref>
*[http://www.ncbi.nlm.nih.gov/pubmed/8241557 Evidence for stimulus access to taste cells and nerves during development: an electron microscopic study.] <ref><pubmed>8241557</pubmed></ref>

==History of Discoveries==

{|"class=wikitable sortable" border="1"
|- bgcolor="#89CFF0"
! scope="col" | Date
! scope="col" | Significant Discovery
|- bgcolor="#BCD4E6"
|'''350BC'''
|Aristotle writes about the basic tastes, sweet and bitter, which can be modified, he says, by salty and acidic.
|-bgcolor="#89CFF0"
|style=white-space:nowrap|'''1901'''
|D. Hanig publishes a paper containing data of taste sensitivity in different regions of the tongue. The data are later misinterpreted, giving rise to the myth of the ‘tongue map’
|-bgcolor="#BCD4E6"
|style=white-space:nowrap|'''1908'''
|Fifth basic taste discovered: savouriness, described as umami, which is conferred by glutamate.
|-bgcolor="#89CFF0"
|style=white-space:nowrap|'''1931'''
|Bitter taste sensitivity found to vary among humans (1)
|-bgcolor="#BCD4E6"
|style=white-space:nowrap|'''1931-32'''
|Genetecists confirm findings about sensitivity to bitter tasting PTC and discover non-tasting is a recessive genetic trait (2,11)
|-bgcolor="#89CFF0"
|style=white-space:nowrap|'''1939'''
|Geneticists show that chimpansees like humans, vary in their ability to perceive the bitterness of PTC
|-bgcolor="#BCD4E6"
|style=white-space:nowrap|'''1992'''
|Discovery of gustucin, a teste cell-specific G-protein, in the taste buds. Gustucin is later shown to mark bitter, umami and sweet cells (13)
|-bgcolor="#89CFF0"
|style=white-space:nowrap|'''1992'''
|Discovery of gustucin, a teste cell-specific G-protein, in the taste buds. Gustucin is later shown to mark bitter, umami and sweet cells (13)
|-bgcolor="#BCD4E6"
|style=white-space:nowrap|'''1996'''
| Witt M and Reutter K of the Source Department of Anatomy, Technical University Dresden, Germany, carried out a transmission electron microscopy study to investigate the embryonic and fetal development of Human taste buds. Their results suggest an "at least dual function of embryonic/fetal taste buds", including non-gustatory, paracrine functions prior to the 14th week and gustatory after the 14th week. PMID 8955790
|-bgcolor="#89CFF0"
|style=white-space:nowrap|'''2000'''
|First taste sonsors, the T2R receptors, discovered (3)
|-bgcolor="#BCD4E6"
|style=white-space:nowrap|'''2001'''
|The sweet receptor is discovered (5): a combination of TaR2 and T1R3.
|-bgcolor="#89CFF0"
|style=white-space:nowrap|'''2002'''
|Amino acid detector, T1R1 and T1R3 identified (6) = Umami
|-bgcolor="#BCD4E6"
|style=white-space:nowrap|'''2005'''
|Sweet taste receptor found (15) in the GI tract
|-bgcolor="#89CFF0"
|style=white-space:nowrap|'''2006'''
|Cells for sour taste discovered, identified by PKD2L1 (4-7)
|-bgcolor="#BCD4E6"
|style=white-space:nowrap|'''2007'''
|Harlow DE, Barlow LA of the Department of Cell and Developmental Biology, Rocky Mountain Taste and Smell Center, University of Colorado Denver Health Sciences Center provide evidence of the '''embryonic origin of gustatory cranial sensory neurons''' PMID 17826760
|-bgcolor="#89CFF0"
|style=white-space:nowrap|'''2009'''
|The Car4 receptor, which senses the carbon dioxide in fizzy drinks is found on sour cells (8)

A study by Hevezi P et al, presents the first comprehensive characterization of gene expression in primate taste buds, as opposed to previous studies which focused on rodents. PMID 19636377
|-bgcolor="#BCD4E6"
|style=white-space:nowrap|'''2010'''
|ENaC identified as the sodium-salt taste receptor (9)
|}

*[http://www.nature.com/nature/journal/v486/n7403_supp/fig_tab/486S2a_F1.html Gustatory system: The finer points of taste] <ref><pubmed>22717400</pubmed></ref>

==Adult Tongue and Taste Buds – Structure and Function==

The tongue is for tasting, swallowing, and speech.The tongue is located on the floor of the oral cavity, It is a muscular structure with sensory units crowning. The tongue is divided into an anterior two thirds and a posterior one third. These regions are divided by a V-shaped groove at the back of the tongue (sulcus terminalis). The anterior two thirds of the tongue is covered by stratified squamous epithelium, It contains a roughened surface and has projections called papillae that vary in shape and number. The most numerous papillae are the filiform papillae, which function to provide a surface that aids in holding food on the tongue during chewing. The larger, less numerous fungiform papillae are scattered among the filiform papillae where as the Circumvallate papilae form a wide V at the sulcus terminalis. There are no papillae or taste buds located on the posterior third of the tongue, having mucosal folds and the lingual tonsils instead.

'''The Image Below is a very simplistic Hand drawn Diagram of the surface of the Tongue showing the locations of the different papillae & and also the sulcus terminalis, This image indicates the tongue from an above veiw'''

{|
| [[Image:Drawing of Tongue.png|500px]]

The functional unit of the taste bud is a taste cells, there are between 50 and 100 taste cells in each taste bud these taste cells represent all 5 different tastes. Historically is was believed that different areas of the tongue were responsible for different taste sensations although this has since been disregarded.[http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/W/Welcome.html] The papillae contain taste buds which are connected to the oral cavity via a taste pore, the function of the taste bud is to transmit a chemical signal from the oral cavity to a taste cell, this chemical signal is the converted into an electrical impulse and delivered to the brain via nerve fibres for interpretation.

'''The Image Below is a very simplistic Hand drawn Diagram of a taste bud, in an extreme close up, cross section view of the the taste bud unit, not to scale'''

[[File:Taste_bud_1.jpg]]

==Taste Map==

==Abnormalities==
(try to include technologies to detect abnormalities during pregnancy)

===Knocking out P2X Receptors===

Gustatory abnormalities has not been widely researched and what has been researched has been through animal testing, most commonly we have found on mice.

In Huang, 2008 [PMID:21940456] this team used the release of the neurotransmitter, ATP (adenosine triphosphate) as a quantitative measurement of gustatory sensation and taste. This was done by using a comparison of wild type (WT) and double knockout (DKO) mice. P2X receptors, P2X2 and P2X3 were knocked out in the DKO mice. The premise of this article was that knocking out P2X receptors reduces transmitter secretion of ATP in taste buds, therefore they cannot taste.

It should be noted that the taste buds in DKO are functional, but are not stimulated by the administration of tastants.

The transmission of release of ATP is secretion through gap junction hemichannels (pannexin 1 gap junction).

When both P2X2 and P2X3 are knocked out, no taste is elicited. However they found that if either P2X2 OR P2X3 was knocked out there was a taste response. So the inference made from this is that if one of the two receptors from the P2X family was knocked out there still can have taste response. The WT mice showed significant stimulation by tastants whereas DKO had little to no stimulation of ATP release.

'''Insert image 4 from article here'''

===FGF signalling and genes===

Sprouty, or ''Srpy'', genes have been related to regulating the development of circumvillate papillae (CVP). The CVP are large dome shaped papillae, which form a 'V' just in front of the terminal sulcus.

By knocking out ''Spry'' genes using mice which had ''Spry1'' and ''Spry2'' knocked out showed that the number of CVP doubled. However, when Fibroblast Growth Factor gene ("Fgf10") was absent, the number of CVP was significantly reduced, if not completely absent. The correlation between ''Spry1/2'' and ''Fgf10'' is that ''Spry1/2'' antagonises "Fgf10" to limit the size of the CVP progenitor placode. Exclusive expression of ''Fgf10'' in the mesenchyme is necessary for the formation of CVP.

'''This image shows the CVP stained with H&E and scanned by Scanning Electron Microscope (SEM)'''
[[File:CVP of WT(top) and DKO(bottom) mice with H&E and SEM.png]]

Taste buds develop from the mesenchyme but require local signalling to properly differentiate. Some signalling factors for proper development of taste buds besides FGF are: Sonic Hedgehog (SHH), Bone Morphogenetic Proteins (BMPs), Epidermal Growth Factor (EGF).

Additionally, this proves that the anterior and posterior developments of the tongue are derived from embryonic tissues, where the anterior tongue is derived fromt he ectoderm and the posterior tongue is derived from the endoderm.

==Current Research==
We have an evolving understanding of Embryonic Taste development, through the use of state-of-the-art technology and research techniques we are able to make brilliant discoveries that continue to connect the dots of this amazing natural process of human development.
The majority of research in taste development is involving mice, these mammals show similar embryonic pathways to humans and research is performed in ethical and humane methods.

'''the below image shows histological stains of a mice tongue'''

[[File:Histology.jpg]]

In an animal study using mice by Suzuki Y, Ikeda K, Kawakami K.(2011) Firstly nominating "Six Genes" as a major component in gustatory development, stating that deficiencies in certain Six genes (specifically Six1 & Six4) leads to poor development. Their research also highlights evidence of cooperative relationships between Six genes for normal advance. Understanding the role of certain genes along with the intrinsic relationships they hold is crucial for the ability to identify possible causes and correction of any abnormalities <ref><pubmed>21978088</pubmed></ref>
Another Animal Study involving mice explores a new idea of Neural crest contribution in taste development, specifically the development of papillae and taste buds. Liu HX, Komatsu Y, Mishina Y, Mistretta CM. (2012) suggest that Neural crest cells travel to the location of the tongue in early embryonic stages, gain epithelium phenotypes, multiply and then differentiate to eventually form taste papillae. Appreciating embryonic courses allows constant monitoring throughout expansion of the foetus.<ref><pubmed>22659543</pubmed></ref>
In an animal study conducted by Rothova M, Thompson H, Lickert H, Tucker AS.(2012) exploring the historically debated issue of endoderm contribution to tongue development showed promising evidence that position of taste buds are patterned by the border of ectoderm and endoderm derivative epithelium. <ref><pubmed>ref>22581563</pubmed></ref> Research by Ozdener H, Spielman AI, Rawson NE.(2012) developing a culture which allows taste cells to survive for up to 12 months, empowers researchers to study the processes of proliferation, differentiation and function. <ref><pubmed>ref>22643728</pubmed></ref>
Brain-derived neurotrophic factor (BDNF) was identified to promote gustatory neuron development, along with identifying the embryonic precursor populations for cranial ganglia in mice through the use of fate mapping in a study by Harlow, Yang, Williams, Barlow (2011)<ref><pubmed>ref>PMC2674259</pubmed></ref>
The WNT gene family has a function of signally proteins for various reason such as development, In 2010 Liu, Staubach Grosse, Walton, Saims, Gumucio, Mistretta explored recent findings on the role of WNT's in tongue and papillae development, Concluding that WNT/β-catenin is essential for fungiform papillae differing to WNT5a which proved to be principle in tongue development. <ref><pubmed>ref>PMC2768563</pubmed></ref>

'''The below image shows and example of tongue abnormalities, this is called "double tongue" each side has independent movement'''
[http://www.surgicalneurologyint.com/article.asp?issn=2152-7806;year=2012;volume=3;issue=1;spage=23;epage=23;aulast=Manjila]
[[File:Abnormal of tongue.jpg]]

==Useful links==

==Glossary==

==Image gallery==

== References ==
<references/>

==Glossary==

==External Links==
{{External Links}}

--[[User:Z8600021|Mark Hill]] 12:22, 15 August 2012 (EST) Please leave the content listed below the line at the bottom of your project page.

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