Welcome to the 2014 Embryology Course!
- Each week the individual assessment questions will be displayed in the practical class pages and also added here.
- Copy the assessment items to your own page and provide your answer.
- Note - Some guest assessments may require completion of a worksheet that will be handed in in class with your student name and ID.
|Individual Lab Assessment|
|Lab 12 - Stem Cell Presentation Assessment||More Info|
- 1 Lab Attendance
- 2 Online Assignment 1
- 3 Online Assignment 2
- 4 Online Assignment 3
- 5 Online Assignment 4
- 6 Online Assignment 5
- 7 Online Assignment 6
- 8 Online Assessment 7
- 9 Online Assessment - Peer Reviews
- 10 Online Assessment 9
--Z3414648 (talk) 11:11, 20 August 2014 (EST) Lab 2 I did not put my signature in my lab attendance last week however I did attend. The week 2 lab involved two guest researches discussing meiosis in mammalian oocytes and age-related vulnerability and the reproductive technology revolution.
--Z3414648 (talk) 11:12, 20 August 2014 (EST) Lab 3
--Z3414648 (talk) 11:48, 27 August 2014 (EST)
--Z3414648 (talk) 11:10, 3 September 2014 (EST)
--Z3414648 (talk) 11:39, 10 September 2014 (EST)
--Z3414648 (talk) 12:07, 17 September 2014 (EST)
--Z3414648 (talk) 11:04, 24 September 2014 (EST)
--Z3414648 (talk) 11:22, 8 October 2014 (EST)
--Z3414648 (talk) 11:08, 15 October 2014 (EST)
--Z3414648 (talk) 11:07, 22 October 2014 (EST)
--Z3414648 (talk) 12:14, 29 October 2014 (EST)
Online Assignment 1
Matteo A Avella, Boris Baibakov, Jurrien Dean A single domain of the ZP2 zona pellucida protein mediates gamete recognition in mice and humans. J. Cell Biol.: 2014, 205(6);801-9 PubMed 24934154
This article from PubMed explores the role of the ZP2 receptor and protein in female mice fertility and species-specific nature of the fusion of spermatozoa and oocyte during successful fertilisation. ZP2 is a glycoprotein found in a region of the extracellular oocyte-surrounding zona pellucida . Polyspermy is an abnormal and detrimental process where membrane fusion occurs between one oocyte and more than one spermatozoa. It is inefficient for more than one spermatozoa to bind to the oocyte because only one male and female gamete are required for successful fertilisation. The authors of this article used gamete samples from both mice and human origin to illustrate their findings.
The authors used various materials and scientific methods in order to achieve their results. There were extensive, complex and repetitive biochemical and transgenic variations made in order to manipulate the gene expression and protein synthesis occurring in the test subjects, in this case mice. In order to control which cells could be genetically modified to express human or mice ZP2 protein, they scientists needed to first produce transgenic mouse lines from embryonic stem cells that had not yet differentiated into any of the ZP1, ZP2, ZP3 or ZP4. They created Bacterial Artifical Chromosomes carrying either the mouse or human form of the ZP2 gene and these were transformed into bacterial cells containing the gamma prophage. The recombinants could be identified by growing the transformed cells on minimal media with galactose. Once the transgenic mice line was established, they were genotyped using TP2 specific primers in extensive PCR reactions. The eggs and embryos were examined under the microscope and the scientists carried out immunohistochemistry. They examined the fertility of the females with and without the ZP2 binding ability through mice and human sperm assays. They also experimented with in vitro fertilisation of the female mice oocyte with mice sperm and then human sperm.
These scientists accumulated results which revealed with following things. The transgenic female mice that did not express ZP2 in their zona pellucida where sterile. Female mice that were genetically modified to express the four human ZP proteins (ZP1, ZP2, ZP3 and ZP4) were recognised by human sperm to carry our successful fertilisation. However the female mice that did not express the human ZP2 protein did not attract the human sperm for fertilisation. This illustrated the species-specific gamete fusion that occurs in human fertilisation.
Kirstine Kirkegaard, Johnny Juhl Hindkjaer, Hans Jakob Ingerslev Hatching of in vitro fertilized human embryos is influenced by fertilization method. Fertil. Steril.: 2013, 100(5);1277-82 PubMed 23909991
This journal article from PubMed compares the nature of embryo hatching between two different types of artificial fertilisation of a female gamete: in vitro fertilisation (IVF) and intracytoplasmic sperm insemination (ICSI). 'Hatching' is a term given to the process that occurs at around day 6 of embryo development, post zygote production, and it is where the blastocyst containing the maternal and paternal pronulei escapes the zona pellucida. In vitro fertilisation is where female follicles are isolated from the ovary and are exposed to spermatozoa. The spermatozoa acrosomal head naturally fuses to the zona pellucida of the female follicle and from there, there is no more external manipulation. The genetic material from the sperm mixes with the genetic material of the occyte resulting in fertilisation and a zygote. In intracytoplasmic sperm insemination, a fine needle is used to inject the sperm through the zona pellucida directly into the oocyte.
These scientists performed a study in a fertility clinic and carried out in vitro fertilisation, embryo culture and embryo grading in order to obtain the results they wanted. Oocytes were inseminated either via IVF or ICSI and then the embryos were cultured and tested for successful fertilisation using an embryoscope. The grade the embryos were given was based on the size of the blastocele cavity and the cohesiveness of the inner cell mass. The embryos with the best morphology were used for further testing. The embryoscope took images every 20 minutes and this enabled the researchers to compare the nature of embryo hatching from the two different types of artificial fertilisation techniques.
The results from these experiments showed there were two main types of spontaneous hatching which were specific for the two types of artificial fertilisation. One type of hatching was initial finger like projections reaching out of the zona pellucida before eventually the blastocyst emerged. The other type was spontaneous complete hatching out of the zona pellucida where the embryo completely ruptured through without the initial projections. The first type was mainly seen with the ICSI technique and the sudden rupture hatching was seen with the IVF technique.
--Mark Hill These are good summaries of these 2 research articles (5/5)
Online Assignment 2
Online Assignment 3
- Nataša Ristić, Nataša Nestorović, Milica Manojlović-Stojanoski, Ivana Medigović, Svetlana Trifunović, Branka Sošić-Jurjević, Verica Milošević Exposure to dexamethasone reduces pituitary volume and gonadotropic cell number in rat fetuses. Acta Histochem.: 2014, 116(5);973-80 PubMed 24816519
- Montse Garcia-Lavandeira, Víctor Quereda, Ignacio Flores, Carmen Saez, Esther Diaz-Rodriguez, Miguel A Japon, Aymee K Ryan, Maria A Blasco, Carlos Dieguez, Marcos Malumbres, Clara V Alvarez A GRFa2/Prop1/stem (GPS) cell niche in the pituitary. PLoS ONE: 2009, 4(3);e4815 PubMed 19283075
- Olga Medina-Martinez, Felipe Amaya-Manzanares, Chaomei Liu, Marisela Mendoza, Rina Shah, Li Zhang, Richard R Behringer, Kathleen A Mahon, Milan Jamrich Cell-autonomous requirement for rx function in the mammalian retina and posterior pituitary. PLoS ONE: 2009, 4(2);e4513 PubMed 19229337
- Minoru Okamoto, Suguru Hayase, Masaaki Miyakoshi, Tsubasa Murata, Shioko Kimura Stem cell antigen 1-positive mesenchymal cells are the origin of follicular cells during thyroid regeneration. PLoS ONE: 2013, 8(11);e80801 PubMed 24278321
- A J Forhead, A L Fowden Thyroid hormones in fetal growth and prepartum maturation. J. Endocrinol.: 2014, 221(3);R87-R103 PubMed 24648121
- Aurore Carre, Latif Rachdi, Elodie Tron, Bénédicte Richard, Mireille Castanet, Martin Schlumberger, Jean-Michel Bidart, Gabor Szinnai, Michel Polak Hes1 is required for appropriate morphogenesis and differentiation during mouse thyroid gland development. PLoS ONE: 2011, 6(2);e16752 PubMed 21364918
Online Assignment 4
Therapeutic Cord Stem Cell Use
The article written by S. Gopinath et al. looks into the therapeutic use of human umbilical cord blood (hUCB)-derived stem cells in reversing pathological hypertrophy of heart tissue in rats. It is an extensive research paper that uses the pre-existing knowledge that cord stem cells are pluripotent and have the potential to differentiate into any tissue of the body. Using this they investigated the ability for hUCB-derived stem cells to reverse the pathological hypertrophy that occurs when rats are induced with doxorubicin (DOX). Doxorubicin is a cancer-treating drug but is also known to induce cardiac hypertrophy. Cardiac hypertrophy involves the increase of size of cardiomyocytes, increased protein synthesis, increased interstitial fibrosis and higher organisation of a sarcomere. However there is also increased frequency of apoptosis that is dangerous considering myocytes have a limited self-renewal capacity. Hence if hUCB-derived stem cells have a cardiomyogenic potential, they could be used to reverse heart failure conditions.
One key result that came about during this investigation was that after 24 hours of co-culture of normal rat cardiomyocytes and hUCB-derived stem cells, the structure of the red stained hUCB-cells began to look like myocytes. Immunocytochemistry staining showed that these new myocytes stained positive for molecules found in normal myocytes including connexion 43 and N-cadherin. There was also a clear image of striated cardiac α-actinin. Upon physical examination, the researchers found that these new myocytes beat in a strong, synchronised manner and also exhibited tight electrical coupling with the normal rat myocytes. Another finding was that hUCB-derived stem cells were able to decreases the apoptotic activity of DOX induced cardiac cells. This was indicated by the decrease expression of apoptotic proteins like caspase-9 and caspase-3 from the initially highly active apoptosis in the DOX-induced cells.
Finally, the researchers were able to prove a significant finding involving the ability for hUCB-derived stem cells to reverse the pathological hypertrophy induced by the DOX. Part of the reason for this result was that the hUCB-derived stem cells were replacing the dead myocytes and there was increased paracrine secretion of IGF-1. This is significant because IGF-1 (insulin-like growth factor 1) is known to increase cell proliferation and inhibit apoptosis.
Sreelatha Gopinath, Sravan K Vanamala, Christropher S Gondi, Jasti S Rao Human umbilical cord blood derived stem cells repair doxorubicin-induced pathological cardiac hypertrophy in mice. Biochem. Biophys. Res. Commun.: 2010, 395(3);367-72 PubMed 20382121
There are a number of developmental vascular "shunts" present in the embryo that are closed postnatally. Identify these shunts and their anatomical location.
1. Foramen ovale: a shunt in the aortic arch is present in the embryo meaning the blood flow bypasses the pulmonary circulation. The blood can flow from the right atrium to the left atrium without going via the pulmonary circuit.
2. Ductus venosus: a shunt that exists between the left umbilical vein and the inferior vena cava. It mean the oxygenated blood from the placenta bypasses the liver on the way to the embryo
3.Ductus arteriosus: a shunt that exists between the proximal descending aorta and the pulmonary artery. This is important in allowing the blood to run from the right ventricle to the aorta without entering the prenatal fluid-filled lungs.
Edward M Dzialowski, Tushar Sirsat, Saskia van der Sterren, Eduardo Villamor Prenatal cardiovascular shunts in amniotic vertebrates. Respir Physiol Neurobiol: 2011, 178(1);66-74 PubMed 21513818
--Mark Hill very good (5/5)
Online Assignment 5
Congenital Pulmonary Airway Malformation
Congenital Pulmonary Airway Malformation (CPAM) is an abnormality that comes as a result of abnormal respiratory system development from week 4 to 10 of gestation. There are varying classes of CPAM depending on the level of differentiation of alveoli, the functional unit of the respiratory system, and the location of the abnormality. Although not completely understood, it is believed that this abnormality arises from unusual lung budding of the foregut endoderm during week 4 to 5 of development. Depending on the malformation observed, the embryological timing can help explain the deformity. Type I CAMP is where there is a localised cystic lesion in a lobe of the lung with pseudostratified ciliated columnar epithelium and relatively well differentiated alveolar cells.  This suggests the malformation occurred during week 7 to 10 which is when bronchial cartilage and smooth muscle form in the fetus.
Congenital Pulmonary Airway Malformations usually involve cystic changes in terminal bronchioles of the lung and are usually accompanied by recurrent pulmonary infections, lung abscesses and intra and extra lobar sequestration. They are usually recognised in the neonate within the first 2 years of life however they can also lie unobserved until later in life. CPAM in an adult can cause massive hemoptysis (coughing up blood) and respiratory distress but rarely causes symptoms like fever, headache, weight loss or chest pain that are typical of other respiratory disorders like pneumonia. If the malformation is isolated to a small part of a lobe, it can be removed surgically but type III CPAM has poor prognosis as it usually involves large lesions that are dispersed throughout the majority of a lobe of the lung.
Another theory on the cause of Congenital Pulmonary Airway Malforamtion is arrested development of the bronchial tree during week 6 to 7 of lung development. Furthermore it has been found that the thyroid transcription factor 1 (TTF1) plays a role in lung epithelium differentiation and lung development. It is found only in the lung, thyroid and in some parts of the brain so mutation or deletion to the gene coding for TTF1 could contribute to malformation of lung epithelium resulting in CPAM. 
- Kirti Gupta, Venkataseshan Sundaram, Ashim Das, Praveen Kumar Extralobar sequestration associated with congenital pulmonary airway malformation (CPAM), type I: an autopsy report. Fetal Pediatr Pathol: 2011, 30(3);167-72 PubMed 21355683
- Hilary A Enuh, Edward L Arsura, Zaza Cohen, Keith T Diaz, Jay M Nfonoyim, Phillip J Cosentino, Jessie K Saverimuttu A fatal case of congenital pulmonary airway malformation with aspergillosis in an adult. Int Med Case Rep J: 2014, 7;53-6 PubMed 24672262
- Ryan J McDonough, Alexander S Niven, Keith A Havenstrite Congenital pulmonary airway malformation: a case report and review of the literature. Respir Care: 2012, 57(2);302-6 PubMed 21762550
--Mark Hill (5/5)
Online Assignment 6
I have found a paper written in 2009 by a group of researchers from the University of California who have investigated the role of DNA methyltransferase 1 (Dnmt1) in pancreas development. Their paper Loss of Dnmt1 catalytic activity reveals multiple roles for DNA methylation during pancreas development and regeneration looks at the role of Dnmt1 in the development of the endodermal originating endocrine, duct and acinar cells of the pancreas. It uses a deductive method involving acquired Dnmt1 mutant zebra fish and looking at which pancreatic cells have inhibited, improved or unchanged growth and development.
This paper is useful in consolidating our understanding of the control of various endodermal cells involved in pancreas growth and function. Dnmt1 is an enzyme that controls gene regulation and helps maintain chromosomal integrity. This paper found that in the early stages of pancreas development, Dnmt1 is a critical part of acinar cell development but not for beta cells or pancreatic duct cells. Their investigation using Zebrafish as a model showed that without this enzyme, the pancreas formed and then degenerated 84h post fertilization (hpf). With further investigation, they found that by 100hpf, almost all the acinar cells had undergone apoptosis but the endocrine and pancreatic duct cells still maintained integrity and remained functional.
Although this paper uses zebrafish rather than humans to investigate pancreas development, it still reveals a relative timescale of the organ development. It also highlights the complex nature of endocrine organ development and how many enzymes are involved in assuring correct growth takes place. 
- Ryan M Anderson, Justin A Bosch, Mary G Goll, Daniel Hesselson, P Duc Si Dong, Donghun Shin, Neil C Chi, Chong Hyun Shin, Amnon Schlegel, Marnie Halpern, Didier Y R Stainier Loss of Dnmt1 catalytic activity reveals multiple roles for DNA methylation during pancreas development and regeneration. Dev. Biol.: 2009, 334(1);213-23 PubMed 19631206
Embryonic layers and tissues contributing to developing teeth:
- Ectoderm contributes to tooth enamel epithelium
- Neural crest derived mesenchyme contributes to dentin and pulp of the teeth
- The teeth develop around the stomodeum which is the origin of the oral cavity
- Some argument around vertebrates that have pharyngeal teeth, suggesting there is a pharumgeal endodermal origin involved as well, however it isn’t as thoroughly understood.
Vladimír Soukup, Hans-Henning Epperlein, Ivan Horácek, Robert Cerny Dual epithelial origin of vertebrate oral teeth. Nature: 2008, 455(7214);795-8 PubMed 18794902
--Mark Hill A useful paper related to imprinting in zebrafish (as a model organism). It would have been good to show relevance to other species pancreas development. Tooth information OK. (4/5)
Online Assessment 7
Embryonic Development of the Human Ovary
Human gonad development begins around week 5 of embryological growth and the sex of the fetus depends on the X or Y chromosomal contribution from the male and female gametes at fertilization. Until around week 10, the human gonads are considered to be bipotential meaning they have the ability to differentiate into male testes or female ovaries.  Gonad development is often referred to as urogenital development since it is closely related to the urinary system growth. Around week 4 the primordial germ cells are established at the site of umbilical vesicle near the origin of the allantois. In week 5 there is a thickening of the mesothelium on the medial side of the mesonephros which is the primitive kidney.
During embryonic folding, the dorsal part of the umbilicus is incorporated into the embryo and by week 5, there is migration of the germ cells to the genital ridge. By week 6, there is proliferation of the epithelium and mesenchyme at the genital ridge that results in finger-like projections of epithelium forming genital cords producing an external cortex and internal medulla. The primordial germ cells migrate into the mesenchyme of the genital cords and this is controlled by various genes like stella and fragilis. In addition to the genital folds, by week 6 there are two types of genital ducts: mesonephric and paramesonephric. The mesonephric contributes to male gonad development whereas the paramesonephric contributes to female gonad development.
The paramesonephric duct is also known as the Mullarian duct and in men there is an anti-mullarian gene that when switched on is responsible for the degradation of this duct. The Mullarian duct is a result of the invagination of the coelomic epithelium through the mesonephros.  The cranial end of the duct opens to the peritoneal cavity whereas the caudal end runs parallel and lateral to the Wolfian tube until it crosses over ventrally and fuse to form a y shaped uterovaginal primordium, the eventual uterus and vagina. An XX genotype results in a female embryo and this is because testosterone is not produced, resulting in lack of maintencance of the mesonephric duct, no expression of anti-mullarian hormone hence maintenance of the paramesonephric duct. From week 10 onwards there is further gonad and external genital growth forming the ovaries, uterus and vagina.
Historic Image of Human Urogenital Development
Fig. 1109. Urogenital Sinus of Female Human Embryo of 8.5 to 9 weeks old
The Müllerian Ducts (Paramesonephric Ducts)
- Stefanie Eggers, Thomas Ohnesorg, Andrew Sinclair Genetic regulation of mammalian gonad development. Nat Rev Endocrinol: 2014, 10(11);673-683 PubMed 25246082
- Grant D Orvis, Richard R Behringer Cellular mechanisms of Müllerian duct formation in the mouse. Dev. Biol.: 2007, 306(2);493-504 PubMed 17467685
The following chapter links only work with a UNSW connection and can also be accessed through this UNSW Library connection.
|Historic Disclaimer - information about historic embryology pages|
|Embryology History | Historic Embryology Papers)|
The image is from the book Grays Anatomy from 1918 which can be accessed by the following link:
--Mark Hill Good, but a little too much in the way of reference organisation, which looks like cut-n-paste, also do not cite the textbook please. (4/5)
Online Assessment - Peer Reviews
Project 1: Respiratory system
The intro is very good and the images are a good size but there needs to be some description to make it relevant to the project. Need to edit ‘Conducting Zone’ info since there are some grammatical and spelling errors. Also should have in-text referencing in this section of the project with a long list of all the references at the end. You can go onto other people’s reports to find the coding for this reference style.
The information on the lung development timeline is fantastic but it is a bit dense. Splitting it into bullet points might be a better way of organising it so peers get a more effective learning experience when they read it. In the conducting system under current findings it looks like there has been an attempt to upload an image called “400px” however the link leads nowhere. It has great information, very interesting and concise. However the references at the end of this section should be incorporated at the very end of the wiki page. This would make it flow better.
Excellent images of the diseased lung compared to normal lung, however it might make more sense for these to be under the lung abnormalities subheading. There is excellent information on the historical findings. It has been written in an easy to understand manner and all the information is relevant. There is also excellent referencing and good use of diagrams. However I still think that the references should all be together at the very end of the project page.
The abnormalities section is very in depth however there is a bit too much information. It would be easier to follow and more interesting if there were images associated with the information, or maybe if the information was tabulated that would make it easier to follow. Well done on this project! It is clear that a lot of research has been done outside.
Project 2: Renal system
This is an excellent introduction and gives a great expectation for the information to come later in the project. The current research models section needs to be checked for spelling and grammar. The information here is good but is also very dense and hard to follow. It would be great if you could break it up a bit with bullet points or more images or tables. This style of writing is very professional and would be perfect for a report or essay, however as a wiki page it is too hard to follow. Breaking up the information into bullet point and tables would allow you to guide the reader through a journey of renal system development.
There has clearly been a lot of research and work put into this project and that is very commendable. However on a whole, there is too much information. It’s difficult to read and grasp a wholesome understanding of the renal system when it delves too deep too quickly. One suggestion is giving a more brief explanation of the timeline of nephrogenesis, urethra, ureter and bladder development and then go into more detail in a subheading called “current research findings”. The references under the abnormalities heading should be incorporated at the very end.
Project 3: gastro-intestinal system
This project overall is very good with a lot relevant information. There is some use of images and hand-drawn images that are excellent. It would be good to see more images, perhaps to complement the timeline section. It is clear the group have worked well together to create a wiki page that flows well and covers all the organs of the gastrointestinal system. All the citations formatted correctly and it is good that all the references appear in one long list at the end of the page. There is still room to add tables, maybe to summarise the timeline. Other groups who presented their timelines in a table achieved an element of wiki-sophistication. There are a few spelling errors in some of the sections (specified below) which need to be corrected so as to not interrupt the flow of information when the reader is reading it. Again, there are only minimal errors or problems with this page, overall it is excellent!
The section on the midgut is well presented and thoroughly researched, well done! It is easy to follow and the way it is described makes it easy to imagine visually. However just double check for typos, for example “to that of” is spelt “tot hat of”. Simple error that is easily fixed. These hand drawn images are excellent. The colour coding and minimal use of words is very effective in supporting the written material.
The hindgut section is also well written and there is a lot of extensive information. Also double check for spelling, mesenchyme is spelt “esenchyme” in one of the sentences. This area of the project is lacking images detracting from its readability and level of interest.
Project 4: genital system
This project would benefit from having an introduction to prepare the reader for what is to come and summarise everything briefly. The system development part is interesting and clearly there has been a lot of research put into finding the information. I suggest adding pictures or student-drawn diagrams, particularly of the chromosome and the SRY gene location to make it more comprehendible. If you’re not a geneticist, it can be difficult to picture that much detail at an embryonic level. It is clear you have considered inserting images so it would be important to follow through with that before the final stages of marking. I’m not really sure why you’ve inserted a table here as well since a lot of the information was already covered previously. Maybe use less information in the table. The references at the end of this section should appear at the very end of the wiki page. A lot of other groups have already done that so if you need to copy the formatting, it’s definitely possible. The use of a video on your page is commendable and sets this project above others in that sense. It’s a great idea to have a youtube clip. However, it is 9 minutes long which is a bit long for a student page that is designed to inform students on the genital system on a wholistic scale rather than tackling complicated ideas. Maybe try editing the youtube video so you only use a 30 second or 1minute clip.
The male and female genital development section is clearly presented and the use of bullet points make it easy to follow. However reading the information, it appears that a lot of it I recognised from the lectures. This doesn’t suggest the student explored external embryology sources. On another note, perhaps the lecture on the genital system was very indepth and this student did do research but found all the relevant information had already been covered. None the less, I think it would be advantageous to add a subheading in the section that looks at recent findings. This would broaden the understanding an embryology student can achieve by reading this wiki-page. Also there has been an error uploading an image so that should be fixed.
Although the information is presented well, the bulk of references should be included at the very end of the page. This project is very good but there is still some further research needed, particularly under the current findings subheading. The information presented under the historical findings subheading is quite dense and would benefit from being broken up into a table or simple bullet points. The abnormalities part is excellent and there has clearly been broad research into different embryological resources.
Project 5: Integumentary system
Overall this is an impressive and well researched wiki page incorporating lots of pictures and tables to keep the reader engaged and interested. However there are a few areas that have the potential to be tweaked. Firstly there are references scattered throughout the page. A more attractive way of presenting the references is as a long list at the end of the page. The introduction is clear, concise and short. All the organ development section is well presented and has the right amount of information. It is well structured in the sense that the student introduces the organ, it’s embryonic origin, the fetal growth stage and then goes into slightly more depth in a bullet point form. Along with complementary pictures, this is a very effective way of presenting their topic. This page could be improved by adding student-drawn schematic diagrams to summarise the layers of the skin in particular since histological images can be confusing and unclear to a non-expert embryology student.
The skin development section appears to dwell on the content that was covered in lectures. Considering there appears to be only three references associated with the entire integumentary organ development section, the depth of the information is limited. By doing some more research you might be able to find interesting additional information that can be added. The recent findings section is interesting and the images are great. However the dense block of information and slightly odd formatting make it hard to follow. Perhaps using diagrams to explain the differing gene expression and breaking down the information into bullet points would make it more readable.
The historic findings and abnormalities section is particularly well done. The images complement the minimal yet important points made. I was left wanting to read more into it so that suggests there’s room for further development and a deeper explanation of skin abnormalities.
Project 7: Neural
This project has a great introduction and overview of the brain and spinal cord anatomy. The first image is eye catching however I find it hard to follow and it seems like there is too much information on it. Perhaps it would be better positioned further down in the report after more neural developmental stages have been explained. The timeline section is clear and to the point. There is an excellent use of images to support the information. The fluorescent stained images make the ventricular, subventricular and other cortical layers clear and easy to understand. The information under the brain development section is simple and effective. However there are some terms mentioned that are not explained in enough detail like the specific layering of the cortex. It is a complicated migration process that deserves some more research. It is good that the student has explained gyration and sulcation in this section.
This project is clearly still in progress however the information in the first section of the wiki page indicates a very promising final product. The spinal cord and meninges development section still needs to be written up. If it follows along the course of the brain development section, it will be flawless. The current research models and finding section reveals an in-depth understanding of complex ideas. However for a student embryology wiki page, there is too much detail. If the student wants to illustrate a complicated research finding, images or tables of the results found from this research would help convey the message to the student. A table would help summarise the results in the first current research description, particularly for the results gathered from the different parts of the brain.
The final part of this report on abnormalities is unfinished however the bulk of the information presented already is very good. The images supporting the abnormality are excellent and important for keeping the student reading this page engaged. However there are a few spelling and grammar errors in the neural tube defects section: “which affect the either the brain”, “the openings remain which leas”. There is still room for more research and information on other neural development abnormalities and the subheadings the student has incorporated indicates their intention of adding more information. This report has excellent reference formatting and citation throughout the page. The tables and images are referenced correctly and the long list at the end is very neat.
Project 8: musculoskeletal
This project is still in its early days but the layout and plan is very good. With additional information added to the subheadings, it will be a very interesting student wiki page. Reviewing what has already been completed on this page, it is too content heavy. There are a lot of large chunks of text indicating the student has gone to a lot of effort to find complex research papers. This is further supported by the huge amount of references at the end of the page. However as this is to be a student embryology wiki page, it would help if the passages of text were broken up into bullet points and tables. Furthermore there are no images or student drawn diagrams. These would also help convey the main messages of musculoskeletal development. The sections after tendon development are unfinished and very brief. Furthermore the only in text referencing present is in the first two sections. Citations should be carried through the entire page.
The second trimester muscular development section is particularly clear and to the point. However the information present doesn’t stretch much further than what was covered in the lecture material. By adding diagrams of the pharyngeal arch origins and including further research into this section, its quality will be greatly improved.
--Mark Hill Very good (10/10)
Online Assessment 9
Sensory System Development - The Eye
Embryological eye development is an area of sensory embryology that has recently been the subject of various research papers. A paper that has particular relevance to eye development is by Yao Chen et al, titled Effects of High Salt-Exposure on the Development of Retina and Lens in 5.5-Day Chick Embryo. It was published on the 20th August 2014 making it very current research. Although they used Chick embryos instead of human embryos, the Chick model is very useful for looking at eye development because that sensory system is relatively large in the early stage embryo, hence making it easier to study.
This paper investigates the effect of high salt exposure to the developing embryo particularly on eye, lens and retina shape and development. It compares a control eye that had normal salt exposure with two variations: exposure to 280mosm/l Sodium Chloride (NaCl) solution and 300mosm/l NaCl solution. Once the fertilised chick embryos were treated with these solutions, they were incubated and then H&E stained for analysis of transverse sections. The eye diameter and retina thickness were measured using Image-Pro Plus 6.0, a photography program. The proliferation of cells in the retina were measured using Phospho-Histone P3 immunostaining to measure the expression of the Pax6 gene which is vital in normal retina development.
This report also explains early vertebrate eye development in the embryo. The eye has three main embryonic origins: the optic vesicle, the surrounding mesenchyme and the overlying surface ectoderm. In response to signals from the optic vesicle, the surface ectoderm thickens to form the lens placode and around week 4 disassociates from the surface of the embryo to form a lens vesicle. This lens vesicle will form the actual lens. The optic vesicle invaginates to form an optic cup where the internal layer forms the neuroretina and the outter layer forms the pigmented retinal epithelium. There is also neural crest cell contribution to the development of retinal ganglion cells, cone photoreceptors, rod photoreceptors, bipolar cells and Muller glia cells. The Paired Box 6 gene (Pax6) is also very important for proper development of the eye, eye size, neuronal differentiation and retina development.
The results gathered form this investigation highlighted the detrimental effect high salt intake can have on a developing embryo, in particular eye development. The level of eye deformity increased with increased level of NaCl exposure. The size of the eye decreased significantly, the diameter of the lens decreased and the lens was thinner. These results were gathered by looking at the images after H&E staining. Furthermore, using immunostaining, it was evident that there was decreased expression of the Pax6 gene in high-NaCl embryos. This is very important since it has been found that this gene is expressed during optic vesicle and integration of the surface ectoderm into development of eye structures in the early embryo. If this gene is not expressed due to high salt levels, the embryo will have abnormal eye development. This can be observed in humans who suffer from pan-ocular disorders and in mice models where an under expression of Pax6 leads to the eyeless phenotype. Pax6 is also important during neural crest cell migration specifically the periocular mesenchyme cells that contribution to eye structures. Hence it is clear that this report shows how high levels of salt intake can have detrimental effects on eye development. 
- Yao Chen, Guang Wang, Xiao-Yu Wang, Zheng-Lai Ma, You-Peng Chen, Manli Chuai, Karoline von Websky, Berthold Hocher, Xuesong Yang Effects of high salt-exposure on the development of retina and lens in 5.5-day chick embryo. Cell. Physiol. Biochem.: 2014, 34(3);804-17 PubMed 25170993
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--Mark Hill Paper relates to vision development and possible teratogenic effects of high salt (mosm/l) in chicken model. I am not sure that I have seen much about this in the literature. (4/5)
--Mark Hill Lab 11 assessment?