From Embryology


--Felicia Ton 23:16, 4 August 2010 (UTC)

--Felicia Ton 23:05, 11 August 2010 (UTC)

--Felicia Ton 23:16, 18 August 2010 (UTC)

--Felicia Ton 23:22, 15 September 2010 (UTC)

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--z3241780 22:44, 20 October 2010 (UTC)

Individual Assessment - Lab Questions

Lab 1

Early zygote picture from the Fertilization page

Cell Division Lecture

Process of Fertilization


Lab 2

1. What factor do the syncytiotrophoblast cells secrete to support the ongoing pregnancy?

Shortly after implantation of the blastocyst within the endometrium, the syncytiotrophoblast cells secrete the hormone human Chorionic Gonadotopin (hCG) which stimulates the corpus luteum. hCG supports the ongoing pregnancy by stimulating the corpus luteum to produce increased levels of the essential progesterone and estrogen hormones, thereby preventing menstruation and proliferation of the endometrium. hCG is continually secreted throughout the pregnancy however only at low levels for the final half of the pregnancy.

2. What does the corpus luteum secrete to prevent continuation of the menstrual cycle?

The corpus luteum secretes both progesterone and estrogen, however it is primarily the elevated levels of progesterone that maintain stimulation of the endometrial cells.

Lab 3

1. What Carnegie stages occur during week 3 and week 4?

Carnergie stage 7 to stage 13.

2. What is the change in overall embryo size form the beginning of week 3 to the end of week 4?

The overall change would be between 2.6mm and 4.6mm

3. Approximately when do the cranial (anterior) and caudal (posterior) neuropores close in the human embryo?

The cranial neuropore closes at carnegie stage 11 (23-26 days)

Lab 4

1. Name the vessels that drain into the sinus venosus

The umbilical and vitelline veins, and the cardinal vein

2. What is the fate of the vitelline artery and vitelline vein?

The vitelline artery forms part of the arteries of the GIT and the vitelline veins the portal system

3. Name the 4 layers that constitute the placental barrier

The syncytiotrophoblast, cytotrophoblast, villi connective tissues and fetal capillary endothelial layers

4. What stem cells are found in abundance, and may be harvested from the placenta for therapeutic uses?

Haematopoetic stem cells

Lab 5

1. What is the origin of the gastrointestinal tract smooth muscle?

The Splanchnic mesoderm - which gives rise to the blood vessels , connective tissue and smooth muscle of the gastrointestinal region

2. At what Carnegie stage does the buccopharyngeal membrane begin to break down?

Carnergie stage 11 is when the the breaking down of the buccopharyngeal membrane begins resulting in the opening of the GIT to the amion.

3. Identify the lung developmental stage in late embryonic to early fetal period.

Budding of the lungs from the trachea begins at carnergie stage 22

4. In premature infant birth, which respiratory cell type may not have fully developed?

The type 2 alveolar cells that secrete surfactant

Lab 7

1. Briefly; what is a myotube and how is it formed?

A myotube is an initial multinucleated cell that is an undifferentiated contractile structure. It is formed by the fusion of myoblasts during skeletal muscle development.

2. What changes would I expect to see in the muscle fibre types in my legs if I:

a) Suffered a spinal cord injury

Atrophy of all muscle fibers would be visible due to a lack of usage and contraction

b) Took up marathon running

There would be hypertrophy and increased number of the slow type I muscle fibers in comparison to type IIa,x and b fibers

Lab 10

1. Development of which endocrine organ is affected by low dietary iodine?

The thyroid

2. What are the affects of this deficiency on other non-endocrine system development?

Severe iodine deficiency can result in fetal brain development and neurological cretinism, which is severe stunting of physical and mental growth

3. At approximately what week in development do many endocrine organs appear to begin their function?

Week 10

Lab 12

1. During which trimester does fetal length change the most and when does fetal weight change the most?

The increase in fetal length is most significant during the second trimester. Whereas changes (increase) in fetal weight occurs mostly during the third trimester.

2. What is the name of the theory that links postnatal health with prenatal development?

The Fetal Origins Hypothesis

3. Which hormone initiates and maintains labour during birth and where does it come from?

Oxytocin initiates and maintains labour and is a peptide hormone released from the maternal posterior pituitary gland.

Peer Review

Group 1

Well done overall on your page, I learned a lot from this page alone. The table comparing the different types of transducers and scans, and use of images made the page both engaging and aesthetically appealing. Placing links for further information under each section is something that would probably be useful for all groups on their pages. So well done on that. Your use of tables was very helpful allowing the reader to grasp a conceptual understanding. The abnormalities section is very interesting and highlights the importance of this procedure in prenatal diagnosis. Judging by your references, and detail there has been some extensive research which is great. Something that could be improved would be the How It Works section where the content suddenly becomes quite technically dense. I would suggest simplifying it a little and maybe tailoring the jargon to your audience a little more. That is, someone who knows very little about Ultrasound and it's technicalities. Also, some images under the Abnormalities section would also be helpful

Group 2

Fantastic use of images, it definitely worked to your advantage in engaging your audience's attention. Over all the language used is relatively easy to follow yet informative. As someone has already mentioned, some more editing of spelling is required. The amount of attention to detail is evident in the references which are from a range of sources so well done. I particularly liked that the page covered accuracy and limitations of the diagnostic procedure. Something that lacked clarity in a few other groups. Good use of the table covering the abnormalities, maybe just adjust the cells of the table a little so the spacing appears more even as some cells have very little content while others are completely filled. What about the future of CVS? Is it a procedure that is going to continue as simply diagnostic? Is it being superseded by another procedure? Improvements? Just an idea. Well done overall.

Group 3

Significant research into your topic evident on the page, so well done. The Abnormalities table is both concise and informative. The table along with the hand drawn images and other images makes the page more aesthetically appealing to the reader. I learned quite a lot about this procedure in one sitting which is a credit to your work. A few improvements would be to reference the Ethics and the Disorders Detected sections, maybe break up the text with the use of more tables and dot points which would simplify the content a little as it appears to be very technically dense. A glossary would help your audience in understanding the content more easily and maybe adjusting the jargon so that it's not so scientific but more conceptual. Again, like others have mentioned, some editing in terms of grammatical and spelling errors is needed throughout the page. Good effort.

Group 5

In terms of content, it is informative. Well done. In terms of the page aesthetics, images of fetal fibronectin itself would be useful at the start, and images especially in the Procedure section. The information is there however the use of images throughout the page and tabulating some of your information would make it more engaging and easier to understand. Remember to add a Historical background on the procedure even if it's short seeing as it is still a relatively 'new' procedure. The current research section could be rephrased more to fit into the flow of your page as a whole. Judging by the last sentence, it seems as though it has been put together by simply copy and pasting snippets from different journals. It would be more beneficial if the information given in the journals was analysed, interpreted and then presented while still referencing. This goes for the procedure also. Try to find information, understand it yourself and then 'explain' it to your audience. You will find that the page will be more cohesive as a result. Another point would be to expand the subheadings so that they clearly identify the subject matter being covered under that section as at the moment they are quite vague. Some points which could also be addressed: future of the procedure? The glossary could also be expanded. Good effort.

Group 6

Very informative, well done. The page could do with more images and tables to engage the reader's attention a little more and also allow for some information to be compared and contrasted. Nice effort with the hand drawn pictures. You could also include current research on the uses of the procedure in relation to pregnancy and fetal development as well as the future of the procedure. Although it is not your subject matter it would be helpful for you to briefly define what percutaneous umbilical blood sampling is and emphasise the risks that the method of sample collection are strongly associated with the decision to use this procedure. Aside from that good effort.