Embryology - User contributions [en-gb]

User:Z3332337

2012-10-16T23:23:40Z

Z3332337: /* Identify a recent research article (using the pubmed tags to cite) on iPS cells and summarise in a few paragraphs the main findings of the paper. */

== Lab Attendance ==
Lab 1
--[[User:Z3332337|Z3332337]] 11:49, 25 July 2012 (EST)

Lab 2
--[[User:Z3332337|Z3332337]] 10:15, 1 August 2012 (EST)

Lab 3
--[[User:Z3332337|Z3332337]] 10:17, 8 August 2012 (EST)

Lab 4
--[[User:Z3332337|Z3332337]] 10:24, 15 August 2012 (EST)

Lab 5
--[[User:Z3332337|Z3332337]] 10:19, 22 August 2012 (EST)

Lab 6
--[[User:Z3332337|Z3332337]] 10:15, 29 August 2012 (EST)

Lab 7
--[[User:Z3332337|Z3332337]] 10:16, 12 September 2012 (EST)

Lab 8
--[[User:Z3332337|Z3332337]] 10:10, 19 September 2012 (EST)

Lab 9
--[[User:Z3332337|Z3332337]] 10:03, 26 September 2012 (EST)

Lab 10
--[[User:Z3332337|Z3332337]] 10:02, 3 October 2012 (EST)

Lab 11
--[[User:Z3332337|Z3332337]] 10:14, 10 October 2012 (EST)

Lab 12
--[[User:Z3332337|Z3332337]] 10:15, 17 October 2012 (EST)
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== Lab 1 Assessment ==

=== '''Article Summary''' ===

''Effect of the method of conception and embryo transfer procedure on mid-gestation placenta and fetal development in an IVF mouse model.''

This article discusses the effects of using ''In Vitro Fertilisation (IVF)'' against "In Vivo" mouse models on the fetal development, using birthweight as the a quantifiable variable.

This article showed that IVF fetuses had a lower birthweight than fetuses from In vivo pregnancies.

They implanted sites for all IVF mice had similar implantion sites, however this study shows that IVF mice have higher abortion rates along with a lower birthweight when compared with in vivo embryos. It shows here that IVF embryos are more likely to be delayed in reaching the blastocyst stage when compared to "in vivo". They also show delayed development after the blastocyst stage which may be related to the low birthweight of IVF embryos.

Reference:
Delle Piane, L., Lin, W., Liu, X., Donjacour, A., Minasi, P., Revelli, A., Maltepe, E. and Rinaudo, P.F. (2010). Effect of the method of conception and embryo transfer procedure on mid-gestation placenta and fetal development in an IVF mouse model. European Society of Human Reproduction and Embryology , 25 (8), 2039-2046.

=== '''IVF Nobel Prize''' ===

Professor Robert Edwards won the Nobel Prize in Medicine in 2010.

http://www.abc.net.au/news/2010-10-04/father-of-ivf-wins-nobel-prize/2285078

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== Lab 2 Assessment ==

===Detection of methylation by zygote staining===

[[File:The effect of embryo manipulation on 5meC staining in zygotes z3332337.jpeg]]

Asymmetric anti-5meC staining of the male and female pronucleus after acid-pretreatment has been reported [5], [6], [20], [21] yet was not confirmed by this study. The zygotes used in past studies were commonly generated by in vitro fertilization or subjected to culture in vitro (which provides logistic advantages for the feasibility of such studies). After antigenic unmasking with acid, the smaller (female) pronucleus in zygotes produced by in vitro fertilization (Fig 7A1) and or cultured in vitro (Fig 7A3) showed more anti-5meC staining compared to those collected directly from the oviduct (Fig 7A5). After antigenic unmasking by acid and trypsin, however, high levels of anti-5meC staining were consistently observed in both pronuclei of IVF (Fig 7A2), cultured (Fig 7A4) and fresh PN5 zygotes (Fig 7A6). Analysis of metaphase zygotes showed that culture from the early zygote stage caused variable levels of anti-5meC staining to persist in acid-only treated zygotes (Fig 7B). The level of methylation was assessed further by comparing staining with anti-MBD1 and anti-5meC in fresh and cultured zygotes (Fig 7C). This analysis showed that a similarly high level of MBD1 staining was observed in PN5 cultured (Fig 7C1) and fresh (Fig 7C3) zygotes, yet 5meC staining persisted in an asymmetrical fashion in cultured (Fig 7C7) but not fresh (Fig 7C9) zygotes. After acid and trypsin unmasking the MBD1 staining was lost from both treatments (Fig 7C2,4) and resulted in a similarly high level of staining with anti-5meC in both cultured and fresh zygotes (Fig 7C8,10). No staining was detected with non-immune control antisera for either antibody (Fig 7C5,6 and C11,12). The current results show that manipulation of the early embryo interferes with the maturational changes in zygotic chromatin that results in acid-resistant antigenic masking of 5meC, and this reduced level of masking was greatest in the female pronucleus giving an artifactual appearance of asymmetric demethylation.

Reference:
Li, Y., & O'Neill, C. (2012). Persistence of cytosine methylation of DNA following fertilisation in the mouse. PLoS One., 7(1), e30687. Epub 32012 Jan 30626.
Copyright Li, O'Neill. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

=== Identify a Protein Associated with Implantation ===

A protein associated implantation is Proprotein 6 Convertase (PC6), a serine protease. It is involved in endometrial receptivity and is integral for cellular remodelling by cleavage of scaffolding protein ezrin-radixin-moesin binding phosphoprotein 50 (EBP50). Cleavage event allows for the ezrin protein to integrate the actin cytoskeleton and the plasma membrane, increasing chances of binding and therefore implantation. Knockout mice were used to down-regulate PC6 and results in failure of cleavage of EBP50 and therefore a decrease of healthy embryo implantation when compared to the wild type mice.

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== Lab 3 Assessment ==

=== 1. Identify the difference between "gestational age" and "post-fertilisation age" and explain why clinically "gestational age" is used in describing human development. ===

The "gestational age" is any time between conception and birth, typically measured from the woman's last menstrual period until the current time. Whereas, "post-fertilisational age" is specifically the time after the ovum is fertilised.

"Gestational age" is used to in describing human development because it is measures pregnancy in weeks, as a pregnancy typically lasts 38-42 weeks.

http://www.parentsconnect.com/pregnancy/trying-to-conceive/Gestational_Fetal_Age.html

=== 2. Identify using histological descriptions at least 3 different types of tissues formed from somites. ===

Somites which develop from the paraxial mesoderm, give rise to 3 different types of tissues: dermatome, myotome and sclerotome tissues.

Dorsolaterally there is the:
'''Dermatome''' which forms the dermis and and contributing fibroblasts, &
'''Myotome''' which forms the myoblasts (primordial muscle cells).

Ventromedially there is the:
'''Sclerotome''' which forms the vertebrae and the ribs.

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== Lab 4 Assessment ==

=== 1) Identify the 2 invasive prenatal diagnostic techniques related to the placenta and 2 abnormalities that can be identified with these techniques. ===

'''''Amniocentesis:''''' is where amniotic fluid is extracted with a needle is inserted into the amniotic cavity through the abdominal wall, guided by an ultrasound. This test detects for levels of metabolic by-products, including ''alpha-fetoprotein''. This test is usually administered between 14-16 weeks gestation.

Elevated levels of the afore-mentioned protein may indicate abnormalities regarding the neural tube, such as '''spina bifida''' (unfused vertebrae over spinal cord) and '''anencephaly''' (the end of the neural tube fails to fuse).

'''''Chorionic Villus Sampling (CVS):''''' is where tissue is removed from the chorion layer of the uterine wall, by a needle or a catheter through the cervix, also guided by an ultrasound. This tissue is then karyotyped for molecular and genetic testing, for abnormalities such as '''Trisomy 21''' (aka: Down Syndrome). This test is administered usually in weeks 10-12 of gestation.

It should be noted that abnormalities detected in CVS may be confirmed through amniocentesis.

Reference:
Larsen's human embryology 4th ed. Schoenwolf, Gary C; Larsen, William J, (William James). Philadelphia, PA : Elsevier/Churchill Livingstone, c2009.

=== 2) Identify a paper that uses cord stem cells therapeutically and write a brief description of the paper's findings. ===

Roura, Santiago, Josep-Maria Pujal, and Antoni Bayes-Genis. "Umbilical Cord Blood for Cardiovascular Cell Therapy: From Promise to Fact." Annals of the New York Academy of Sciences 1254, no. 1 (2012): 66-70.

Umbilical Cord Blood (UBC) is a valuable stem cell source and has a great potential for vascular growth and repair. This article indicated that UBC may be used as an alternate source of hematopoietic cytokines (CD133+) which stimulate angiogenesis.

It has been indicated in the therapy for an array of diseases including the reconstitution of a defective immune system, neurological improvement of cerebral palsy, and possibly the treatment of type 1 diabetes. It has also shown improvements in reducing 'graft vs. host' disease in transplant patients due to the presence of Multipotent Stromal Cells (MSCs) found in UCB. MSCs are also found in bone marrow.

Research on animal models through fluorescent angiography has shown that UCB may improve, if not recover, endothelial function from "UCB-MSC differentiation and new microcirculatory vessel formation".

== Lab 7 Assessment==

''(a) Provide a one sentence definition of a muscle satellite cell (b) In one paragraph, briefly discuss two examples of when satellite cells are activated?''

'''a) Muscle satellite cell:''' Is a normally quiescent myogenic cell which holds a reserve stem cell population and becoming activated when muscle is injured.

'''b)''' Satellite cells are activated when new skeletal muscle is being generated of in the instance that muscle is damaged or injured.

''(c) In one brief paragraph, describe what happens to skeletal muscle fibre type and size when the innervating motor nerve sustains long term damage such as in spinal cord injury?''

'''c)''' When there is long term damage to motor nerve cells which prevent normal functioning of the musculoskeletal system the affected muscles generally undergo the process of 'atrophy', or a "wasting away". This is not the muscle dying, but the muscle cells are reducing in size because of a lack of use. Muscle fibre type also changes from fast-twitch fibres to slow twitch.

<pubmed>12757751</pubmed>

== Lab 8 Assessment==
===Student feedback===

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 ☺

Somatosensory

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 ☺

Olfaction

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 ☺

Abnormal vision

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 ☺

Hearing

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 ☺

== Lab 9 Assessment==

===''(a) Identify and write a brief description of the findings of a recent research paper on development of one of the endocrine organs covered in today's practical.''===

<pubmed>21909240</pubmed>

This article indicates that the developing pancreas, both endocrine and exocrine tissue, develops from signals received from the surrounding mesenchyme to the local epithelium from the expanding progenitor cells.

They have shown that mesenchymal cells regulate ancreatic growth both in ealry and late stages of fetal development, including initial proliferation of cells and after cells have differentiated.

This was an in vivo study where they interrupted the Beta-catenin signalling pathway. Beta-catenin is involved in ''"regulating mesenchyme signalling and growth"'', therefore when interrupting this pathway blocked proper pancreas organogenesis in both early and late stages, until the end of the gestation period.

===''(b) Identify the embryonic layers and tissues that contribute to the developing teeth.''===

<pubmed>19266065</pubmed>

The tooth develops from interactions between the dorsal ectoderm within the neural tube which produces WNT6 a signalling protein which interacts with bone morphogenetic proteins (BMPs) from the neural plate. At this point, where the ectoderm and mesenchyme meet (forming ectomesenchyme) there is active cell multiplication where FOXD3 gene is expressed allowing the initial two rows of ectomesenchyme to be expressed.

Cranial neural crest (cnc) cells (also known are odontogenic cells) migrate an populate the pharyngeal arches, from which the maxilla and mandible are derived from the 1st arch.

So although it is thought that teeth arrive exclusively ectoderm, but undergo "mesenchymalisation" which give the teeth the origin of 'ectomesenchyme'.

==Lab 11 Assessment==

===Identify a recent research article (using the pubmed tags to cite) on iPS cells and summarise in a few paragraphs the main findings of the paper.===

<pubmed>21750574</pubmed>

This article used iPS cells to model research ''CDKL5'' mutations, which are a cause of the highest cause of Rett syndrome (a neurological disorder affecting females causing mental retardation).

There is not much currently known about ''CDKL5'''s function inside the cells besides that it is a kinase protein involved in neurons. This article used human iPS cells as a human basis of their study, as the differential properties of iPS are expansive, including neurons. This study derived the cells from one female and male with mutations p.Q347X and p.T288I respectively from fibroblasts.They were attempting find appropriate cellular research models to imitate ''in vitro''studies due to a lack of suitable research into this area, especially from mutated cells that properly to differentiate into neurons, while maintaining x-inactivation in females.

The findings of this paper show that fibroblast derived human iPS cells may be used as a model for research into Rett syndrome.

2012-10-04T14:56:03Z

Z3332337: uploaded a new version of "File:Figure 1 Spry1-2.jpeg": Original Figure Explanation Deletion of Spry2 leads to a duplication of the CVP in the posterior tongue. (A) Cartoon showing location of gustatory papillae in the rodent tongue. (B,C) I

Original Figure Explanation
Deletion of Spry2 leads to a duplication of the CVP in the posterior tongue.
(A) Cartoon showing location of gustatory papillae in the rodent tongue. (B,C) In situ hybridization staining of Shh. Wild-type mice possess a single CVP in the posterior tongue, whereas the CVP is duplicated in Spry2−/− mice (arrowheads). (D,E) SEM images of the tongue at E14.5. Scale bar, 500 µm. (F,G) DAPI fluorescence staining shows that the two CVPs (arrowheads) persist into adulthood in Spry2−/− mice. (D'-G') Higher magnification images of boxed areas. (D',E') Scale bar, 25 µm.

Copyright Petersen et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

{{2012 Student image}}

2012-10-04T02:28:23Z

Z3332337:

An extremely detailed hand drawn image of the human adult tongue.

I (z3332337) 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 Student image}}

User talk:Z3332337

2012-10-03T01:48:31Z

Z3332337: /* ANAT2341 Lab 10 3/10/12 */

User talk:Z3332337

2012-10-03T01:33:52Z

Z3332337: /* ANAT2341 Lab 10 3/10/12 */

User talk:Z3332337

2012-10-03T01:30:19Z

Z3332337: /* ANAT2341 Lab 10 3/10/12 */

2012 Group Project 3

2012-10-03T01:06:45Z

Z3332337: /* Current Research */

=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.

==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]
|}

==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]]

== 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]]

'''Controversial Research - Not Ectodermal Origin'''

==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

2012-10-03T01:03:13Z

Z3332337:

=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.

==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]
|}

==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]]

== 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}}

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.

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{{2012Projects}}

Talk:2012 Group Project 3

2012-10-03T00:53:24Z

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{{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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'''Taste'''
LOVE the opening paragraph! The introduction is very well written, quite easy to read and understand. Very well drawn tongue and the overview of structure and function quite a good way to ease the reader into the page. The histories of the discoveries was really well set out, but i feel like there needs to be a bit more content so that the reader can fully understand what is going on. But it is an overview/glance at the history. The developmental table is very easy to read and very well set out. But because this is the main developmental timeline, should there be more references to really show the evidence? There seems to be a few but not enough to truly show the process. The Abnormalities section, I feel is very well done, (just like most of the page) but the images could be off to the side instead of taking up the amount of space there. I really enjoyed reading this page, not only was it informative but it wasn't painful to read. It was at a level that someone who hasn't yet looked into the area can understand.

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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)

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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)

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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)

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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 ==

Guys,
I just read an article that disputes that taste buds arise from ectoderm but instead arise from local epithelium. Shall we use this as part of current research??
--[[User:Z3332337|Z3332337]] 10:06, 3 October 2012 (EST)

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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?
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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)

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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)

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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)

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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)

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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 talk:Z3332337

2012-10-03T00:51:12Z

Z3332337: /* ANAT2341 Lab 10 3/10/12 */

2012-10-02T03:33:25Z

Z3332337: /* (a) Identify and write a brief description of the findings of a recent research paper on development of one of the endocrine organs covered in today's practical. */

== Lab Attendance ==
Lab 1
--[[User:Z3332337|Z3332337]] 11:49, 25 July 2012 (EST)

Lab 2
--[[User:Z3332337|Z3332337]] 10:15, 1 August 2012 (EST)

Lab 3
--[[User:Z3332337|Z3332337]] 10:17, 8 August 2012 (EST)

Lab 4
--[[User:Z3332337|Z3332337]] 10:24, 15 August 2012 (EST)

Lab 5
--[[User:Z3332337|Z3332337]] 10:19, 22 August 2012 (EST)

Lab 6
--[[User:Z3332337|Z3332337]] 10:15, 29 August 2012 (EST)

Lab 7
--[[User:Z3332337|Z3332337]] 10:16, 12 September 2012 (EST)

Lab 8
--[[User:Z3332337|Z3332337]] 10:10, 19 September 2012 (EST)

Lab 9
--[[User:Z3332337|Z3332337]] 10:03, 26 September 2012 (EST)

----

== Lab 1 Assessment ==

=== '''Article Summary''' ===

''Effect of the method of conception and embryo transfer procedure on mid-gestation placenta and fetal development in an IVF mouse model.''

This article discusses the effects of using ''In Vitro Fertilisation (IVF)'' against "In Vivo" mouse models on the fetal development, using birthweight as the a quantifiable variable.

This article showed that IVF fetuses had a lower birthweight than fetuses from In vivo pregnancies.

They implanted sites for all IVF mice had similar implantion sites, however this study shows that IVF mice have higher abortion rates along with a lower birthweight when compared with in vivo embryos. It shows here that IVF embryos are more likely to be delayed in reaching the blastocyst stage when compared to "in vivo". They also show delayed development after the blastocyst stage which may be related to the low birthweight of IVF embryos.

Reference:
Delle Piane, L., Lin, W., Liu, X., Donjacour, A., Minasi, P., Revelli, A., Maltepe, E. and Rinaudo, P.F. (2010). Effect of the method of conception and embryo transfer procedure on mid-gestation placenta and fetal development in an IVF mouse model. European Society of Human Reproduction and Embryology , 25 (8), 2039-2046.

=== '''IVF Nobel Prize''' ===

Professor Robert Edwards won the Nobel Prize in Medicine in 2010.

http://www.abc.net.au/news/2010-10-04/father-of-ivf-wins-nobel-prize/2285078

----

== Lab 2 Assessment ==

===Detection of methylation by zygote staining===

[[File:The effect of embryo manipulation on 5meC staining in zygotes z3332337.jpeg]]

Asymmetric anti-5meC staining of the male and female pronucleus after acid-pretreatment has been reported [5], [6], [20], [21] yet was not confirmed by this study. The zygotes used in past studies were commonly generated by in vitro fertilization or subjected to culture in vitro (which provides logistic advantages for the feasibility of such studies). After antigenic unmasking with acid, the smaller (female) pronucleus in zygotes produced by in vitro fertilization (Fig 7A1) and or cultured in vitro (Fig 7A3) showed more anti-5meC staining compared to those collected directly from the oviduct (Fig 7A5). After antigenic unmasking by acid and trypsin, however, high levels of anti-5meC staining were consistently observed in both pronuclei of IVF (Fig 7A2), cultured (Fig 7A4) and fresh PN5 zygotes (Fig 7A6). Analysis of metaphase zygotes showed that culture from the early zygote stage caused variable levels of anti-5meC staining to persist in acid-only treated zygotes (Fig 7B). The level of methylation was assessed further by comparing staining with anti-MBD1 and anti-5meC in fresh and cultured zygotes (Fig 7C). This analysis showed that a similarly high level of MBD1 staining was observed in PN5 cultured (Fig 7C1) and fresh (Fig 7C3) zygotes, yet 5meC staining persisted in an asymmetrical fashion in cultured (Fig 7C7) but not fresh (Fig 7C9) zygotes. After acid and trypsin unmasking the MBD1 staining was lost from both treatments (Fig 7C2,4) and resulted in a similarly high level of staining with anti-5meC in both cultured and fresh zygotes (Fig 7C8,10). No staining was detected with non-immune control antisera for either antibody (Fig 7C5,6 and C11,12). The current results show that manipulation of the early embryo interferes with the maturational changes in zygotic chromatin that results in acid-resistant antigenic masking of 5meC, and this reduced level of masking was greatest in the female pronucleus giving an artifactual appearance of asymmetric demethylation.

Reference:
Li, Y., & O'Neill, C. (2012). Persistence of cytosine methylation of DNA following fertilisation in the mouse. PLoS One., 7(1), e30687. Epub 32012 Jan 30626.
Copyright Li, O'Neill. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

=== Identify a Protein Associated with Implantation ===

A protein associated implantation is Proprotein 6 Convertase (PC6), a serine protease. It is involved in endometrial receptivity and is integral for cellular remodelling by cleavage of scaffolding protein ezrin-radixin-moesin binding phosphoprotein 50 (EBP50). Cleavage event allows for the ezrin protein to integrate the actin cytoskeleton and the plasma membrane, increasing chances of binding and therefore implantation. Knockout mice were used to down-regulate PC6 and results in failure of cleavage of EBP50 and therefore a decrease of healthy embryo implantation when compared to the wild type mice.

----

== Lab 3 Assessment ==

=== 1. Identify the difference between "gestational age" and "post-fertilisation age" and explain why clinically "gestational age" is used in describing human development. ===

The "gestational age" is any time between conception and birth, typically measured from the woman's last menstrual period until the current time. Whereas, "post-fertilisational age" is specifically the time after the ovum is fertilised.

"Gestational age" is used to in describing human development because it is measures pregnancy in weeks, as a pregnancy typically lasts 38-42 weeks.

http://www.parentsconnect.com/pregnancy/trying-to-conceive/Gestational_Fetal_Age.html

=== 2. Identify using histological descriptions at least 3 different types of tissues formed from somites. ===

Somites which develop from the paraxial mesoderm, give rise to 3 different types of tissues: dermatome, myotome and sclerotome tissues.

Dorsolaterally there is the:
'''Dermatome''' which forms the dermis and and contributing fibroblasts, &
'''Myotome''' which forms the myoblasts (primordial muscle cells).

Ventromedially there is the:
'''Sclerotome''' which forms the vertebrae and the ribs.

----

== Lab 4 Assessment ==

=== 1) Identify the 2 invasive prenatal diagnostic techniques related to the placenta and 2 abnormalities that can be identified with these techniques. ===

'''''Amniocentesis:''''' is where amniotic fluid is extracted with a needle is inserted into the amniotic cavity through the abdominal wall, guided by an ultrasound. This test detects for levels of metabolic by-products, including ''alpha-fetoprotein''. This test is usually administered between 14-16 weeks gestation.

Elevated levels of the afore-mentioned protein may indicate abnormalities regarding the neural tube, such as '''spina bifida''' (unfused vertebrae over spinal cord) and '''anencephaly''' (the end of the neural tube fails to fuse).

'''''Chorionic Villus Sampling (CVS):''''' is where tissue is removed from the chorion layer of the uterine wall, by a needle or a catheter through the cervix, also guided by an ultrasound. This tissue is then karyotyped for molecular and genetic testing, for abnormalities such as '''Trisomy 21''' (aka: Down Syndrome). This test is administered usually in weeks 10-12 of gestation.

It should be noted that abnormalities detected in CVS may be confirmed through amniocentesis.

Reference:
Larsen's human embryology 4th ed. Schoenwolf, Gary C; Larsen, William J, (William James). Philadelphia, PA : Elsevier/Churchill Livingstone, c2009.

=== 2) Identify a paper that uses cord stem cells therapeutically and write a brief description of the paper's findings. ===

Roura, Santiago, Josep-Maria Pujal, and Antoni Bayes-Genis. "Umbilical Cord Blood for Cardiovascular Cell Therapy: From Promise to Fact." Annals of the New York Academy of Sciences 1254, no. 1 (2012): 66-70.

Umbilical Cord Blood (UBC) is a valuable stem cell source and has a great potential for vascular growth and repair. This article indicated that UBC may be used as an alternate source of hematopoietic cytokines (CD133+) which stimulate angiogenesis.

It has been indicated in the therapy for an array of diseases including the reconstitution of a defective immune system, neurological improvement of cerebral palsy, and possibly the treatment of type 1 diabetes. It has also shown improvements in reducing 'graft vs. host' disease in transplant patients due to the presence of Multipotent Stromal Cells (MSCs) found in UCB. MSCs are also found in bone marrow.

Research on animal models through fluorescent angiography has shown that UCB may improve, if not recover, endothelial function from "UCB-MSC differentiation and new microcirculatory vessel formation".

== Lab 7 ==

''(a) Provide a one sentence definition of a muscle satellite cell (b) In one paragraph, briefly discuss two examples of when satellite cells are activated?''

'''a) Muscle satellite cell:''' Is a normally quiescent myogenic cell which holds a reserve stem cell population and becoming activated when muscle is injured.

'''b)''' Satellite cells are activated when new skeletal muscle is being generated of in the instance that muscle is damaged or injured.

''(c) In one brief paragraph, describe what happens to skeletal muscle fibre type and size when the innervating motor nerve sustains long term damage such as in spinal cord injury?''

'''c)''' When there is long term damage to motor nerve cells which prevent normal functioning of the musculoskeletal system the affected muscles generally undergo the process of 'atrophy', or a "wasting away". This is not the muscle dying, but the muscle cells are reducing in size because of a lack of use. Muscle fibre type also changes from fast-twitch fibres to slow twitch.

<pubmed>12757751</pubmed>

== Lab 8 ==
===Student feedback===

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 ☺

Somatosensory

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 ☺

Olfaction

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 ☺

Abnormal vision

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 ☺

Hearing

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 ☺

== Lab 9 ==

===''(a) Identify and write a brief description of the findings of a recent research paper on development of one of the endocrine organs covered in today's practical.''===

<pubmed>21909240</pubmed>

This article indicates that the developing pancreas, both endocrine and exocrine tissue, develops from signals received from the surrounding mesenchyme to the local epithelium from the expanding progenitor cells.

They have shown that mesenchymal cells regulate ancreatic growth both in ealry and late stages of fetal development, including initial proliferation of cells and after cells have differentiated.

This was an in vivo study where they interrupted the Beta-catenin signalling pathway. Beta-catenin is involved in ''"regulating mesenchyme signalling and growth"'', therefore when interrupting this pathway blocked proper pancreas organogenesis in both early and late stages, until the end of the gestation period.

===''(b) Identify the embryonic layers and tissues that contribute to the developing teeth.''===

Ectoderm...

User:Z3332337

2012-10-02T03:29:25Z

Z3332337:

== Lab Attendance ==
Lab 1
--[[User:Z3332337|Z3332337]] 11:49, 25 July 2012 (EST)

Lab 2
--[[User:Z3332337|Z3332337]] 10:15, 1 August 2012 (EST)

Lab 3
--[[User:Z3332337|Z3332337]] 10:17, 8 August 2012 (EST)

Lab 4
--[[User:Z3332337|Z3332337]] 10:24, 15 August 2012 (EST)

Lab 5
--[[User:Z3332337|Z3332337]] 10:19, 22 August 2012 (EST)

Lab 6
--[[User:Z3332337|Z3332337]] 10:15, 29 August 2012 (EST)

Lab 7
--[[User:Z3332337|Z3332337]] 10:16, 12 September 2012 (EST)

Lab 8
--[[User:Z3332337|Z3332337]] 10:10, 19 September 2012 (EST)

Lab 9
--[[User:Z3332337|Z3332337]] 10:03, 26 September 2012 (EST)

----

== Lab 1 Assessment ==

=== '''Article Summary''' ===

''Effect of the method of conception and embryo transfer procedure on mid-gestation placenta and fetal development in an IVF mouse model.''

This article discusses the effects of using ''In Vitro Fertilisation (IVF)'' against "In Vivo" mouse models on the fetal development, using birthweight as the a quantifiable variable.

This article showed that IVF fetuses had a lower birthweight than fetuses from In vivo pregnancies.

They implanted sites for all IVF mice had similar implantion sites, however this study shows that IVF mice have higher abortion rates along with a lower birthweight when compared with in vivo embryos. It shows here that IVF embryos are more likely to be delayed in reaching the blastocyst stage when compared to "in vivo". They also show delayed development after the blastocyst stage which may be related to the low birthweight of IVF embryos.

Reference:
Delle Piane, L., Lin, W., Liu, X., Donjacour, A., Minasi, P., Revelli, A., Maltepe, E. and Rinaudo, P.F. (2010). Effect of the method of conception and embryo transfer procedure on mid-gestation placenta and fetal development in an IVF mouse model. European Society of Human Reproduction and Embryology , 25 (8), 2039-2046.

=== '''IVF Nobel Prize''' ===

Professor Robert Edwards won the Nobel Prize in Medicine in 2010.

http://www.abc.net.au/news/2010-10-04/father-of-ivf-wins-nobel-prize/2285078

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== Lab 2 Assessment ==

===Detection of methylation by zygote staining===

[[File:The effect of embryo manipulation on 5meC staining in zygotes z3332337.jpeg]]

Asymmetric anti-5meC staining of the male and female pronucleus after acid-pretreatment has been reported [5], [6], [20], [21] yet was not confirmed by this study. The zygotes used in past studies were commonly generated by in vitro fertilization or subjected to culture in vitro (which provides logistic advantages for the feasibility of such studies). After antigenic unmasking with acid, the smaller (female) pronucleus in zygotes produced by in vitro fertilization (Fig 7A1) and or cultured in vitro (Fig 7A3) showed more anti-5meC staining compared to those collected directly from the oviduct (Fig 7A5). After antigenic unmasking by acid and trypsin, however, high levels of anti-5meC staining were consistently observed in both pronuclei of IVF (Fig 7A2), cultured (Fig 7A4) and fresh PN5 zygotes (Fig 7A6). Analysis of metaphase zygotes showed that culture from the early zygote stage caused variable levels of anti-5meC staining to persist in acid-only treated zygotes (Fig 7B). The level of methylation was assessed further by comparing staining with anti-MBD1 and anti-5meC in fresh and cultured zygotes (Fig 7C). This analysis showed that a similarly high level of MBD1 staining was observed in PN5 cultured (Fig 7C1) and fresh (Fig 7C3) zygotes, yet 5meC staining persisted in an asymmetrical fashion in cultured (Fig 7C7) but not fresh (Fig 7C9) zygotes. After acid and trypsin unmasking the MBD1 staining was lost from both treatments (Fig 7C2,4) and resulted in a similarly high level of staining with anti-5meC in both cultured and fresh zygotes (Fig 7C8,10). No staining was detected with non-immune control antisera for either antibody (Fig 7C5,6 and C11,12). The current results show that manipulation of the early embryo interferes with the maturational changes in zygotic chromatin that results in acid-resistant antigenic masking of 5meC, and this reduced level of masking was greatest in the female pronucleus giving an artifactual appearance of asymmetric demethylation.

Reference:
Li, Y., & O'Neill, C. (2012). Persistence of cytosine methylation of DNA following fertilisation in the mouse. PLoS One., 7(1), e30687. Epub 32012 Jan 30626.
Copyright Li, O'Neill. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

=== Identify a Protein Associated with Implantation ===

A protein associated implantation is Proprotein 6 Convertase (PC6), a serine protease. It is involved in endometrial receptivity and is integral for cellular remodelling by cleavage of scaffolding protein ezrin-radixin-moesin binding phosphoprotein 50 (EBP50). Cleavage event allows for the ezrin protein to integrate the actin cytoskeleton and the plasma membrane, increasing chances of binding and therefore implantation. Knockout mice were used to down-regulate PC6 and results in failure of cleavage of EBP50 and therefore a decrease of healthy embryo implantation when compared to the wild type mice.

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== Lab 3 Assessment ==

=== 1. Identify the difference between "gestational age" and "post-fertilisation age" and explain why clinically "gestational age" is used in describing human development. ===

The "gestational age" is any time between conception and birth, typically measured from the woman's last menstrual period until the current time. Whereas, "post-fertilisational age" is specifically the time after the ovum is fertilised.

"Gestational age" is used to in describing human development because it is measures pregnancy in weeks, as a pregnancy typically lasts 38-42 weeks.

http://www.parentsconnect.com/pregnancy/trying-to-conceive/Gestational_Fetal_Age.html

=== 2. Identify using histological descriptions at least 3 different types of tissues formed from somites. ===

Somites which develop from the paraxial mesoderm, give rise to 3 different types of tissues: dermatome, myotome and sclerotome tissues.

Dorsolaterally there is the:
'''Dermatome''' which forms the dermis and and contributing fibroblasts, &
'''Myotome''' which forms the myoblasts (primordial muscle cells).

Ventromedially there is the:
'''Sclerotome''' which forms the vertebrae and the ribs.

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== Lab 4 Assessment ==

=== 1) Identify the 2 invasive prenatal diagnostic techniques related to the placenta and 2 abnormalities that can be identified with these techniques. ===

'''''Amniocentesis:''''' is where amniotic fluid is extracted with a needle is inserted into the amniotic cavity through the abdominal wall, guided by an ultrasound. This test detects for levels of metabolic by-products, including ''alpha-fetoprotein''. This test is usually administered between 14-16 weeks gestation.

Elevated levels of the afore-mentioned protein may indicate abnormalities regarding the neural tube, such as '''spina bifida''' (unfused vertebrae over spinal cord) and '''anencephaly''' (the end of the neural tube fails to fuse).

'''''Chorionic Villus Sampling (CVS):''''' is where tissue is removed from the chorion layer of the uterine wall, by a needle or a catheter through the cervix, also guided by an ultrasound. This tissue is then karyotyped for molecular and genetic testing, for abnormalities such as '''Trisomy 21''' (aka: Down Syndrome). This test is administered usually in weeks 10-12 of gestation.

It should be noted that abnormalities detected in CVS may be confirmed through amniocentesis.

Reference:
Larsen's human embryology 4th ed. Schoenwolf, Gary C; Larsen, William J, (William James). Philadelphia, PA : Elsevier/Churchill Livingstone, c2009.

=== 2) Identify a paper that uses cord stem cells therapeutically and write a brief description of the paper's findings. ===

Roura, Santiago, Josep-Maria Pujal, and Antoni Bayes-Genis. "Umbilical Cord Blood for Cardiovascular Cell Therapy: From Promise to Fact." Annals of the New York Academy of Sciences 1254, no. 1 (2012): 66-70.

Umbilical Cord Blood (UBC) is a valuable stem cell source and has a great potential for vascular growth and repair. This article indicated that UBC may be used as an alternate source of hematopoietic cytokines (CD133+) which stimulate angiogenesis.

It has been indicated in the therapy for an array of diseases including the reconstitution of a defective immune system, neurological improvement of cerebral palsy, and possibly the treatment of type 1 diabetes. It has also shown improvements in reducing 'graft vs. host' disease in transplant patients due to the presence of Multipotent Stromal Cells (MSCs) found in UCB. MSCs are also found in bone marrow.

Research on animal models through fluorescent angiography has shown that UCB may improve, if not recover, endothelial function from "UCB-MSC differentiation and new microcirculatory vessel formation".

== Lab 7 ==

''(a) Provide a one sentence definition of a muscle satellite cell (b) In one paragraph, briefly discuss two examples of when satellite cells are activated?''

'''a) Muscle satellite cell:''' Is a normally quiescent myogenic cell which holds a reserve stem cell population and becoming activated when muscle is injured.

'''b)''' Satellite cells are activated when new skeletal muscle is being generated of in the instance that muscle is damaged or injured.

''(c) In one brief paragraph, describe what happens to skeletal muscle fibre type and size when the innervating motor nerve sustains long term damage such as in spinal cord injury?''

'''c)''' When there is long term damage to motor nerve cells which prevent normal functioning of the musculoskeletal system the affected muscles generally undergo the process of 'atrophy', or a "wasting away". This is not the muscle dying, but the muscle cells are reducing in size because of a lack of use. Muscle fibre type also changes from fast-twitch fibres to slow twitch.

<pubmed>12757751</pubmed>

== Lab 8 ==
===Student feedback===

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 ☺

Somatosensory

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 ☺

Olfaction

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 ☺

Abnormal vision

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 ☺

Hearing

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 ☺

== Lab 9 ==

===''(a) Identify and write a brief description of the findings of a recent research paper on development of one of the endocrine organs covered in today's practical.''===

<pubmed>21909240</pubmed>

This article indicates that the developing pancreas, both endocrine and exocrine tissue, develops from signals received from the surrounding mesenchyme to the local epithelium from the expanding progenitor cells.

They have shown that mesenchymal cells regulate ancreatic growth both in ealry and late stages of fetal development, including initial proliferation of cells and after cells have differentiated.

This was an in vivo study where they interrupted the Beta-catenin signalling pathway. Beta-catenin is involved in "''regulating mesenchyme signalling and growth'', therefore when interrupting this pathway blocked proper pancreas organogenesis in both early and late stages.

===''(b) Identify the embryonic layers and tissues that contribute to the developing teeth.''===

Ectoderm...