From Embryology


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Lab Questions

Lab 2 Questions

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

secrete Human Chorionic Gonadotropin (hCG)

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

produces progesterone and estrogen

Lab 3 Questions

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

Week 3: Carnegie Stages 7 - 9, hallmark features that occur during these stages include gastrulation, development of the notohord and placentation

Week 4: Carnegie Stages 10-13, hallmark features include initial development of the heart, pharyngeal arches and placodes

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

Start of week 3 - stage 7: embryo diameter of 0.4mm

End of week 4 - stage 13: embryo diameter between 3-5mm

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

Stage 11 (aprox 24 days) - cranial neuropore closes within a few hours

Stage 12 (aprox 26 days) - caudal neuropore takes a day to close

Lab 4 Questions

1. Name the vessels that drain into the sinus venosus?

vitelline vein, umbilical vein and the cardinal veins (anterior, common and posterior)

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

the vitelline arteries contribute to adult GIT arteries and later fuse to become the superior mesenteric artery.

the vitelline veins contribute to the adult portal system.

3. Name the 4 layers that constitute the placental barrier?

4 layers are: syncitiotrophoblast, cytotroblast, villi connective tissue and fetal capillary endothelium

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

hematopoietic stem cells (HSCs)

Lab 5 Questions

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

splanchnic mesoderm

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

breakdwon of the buccopharyngeal membrane can be seen during an embryo in stage 11

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

during week 4-5 is the embryonic stage, which is carnegie stage 14 and higher, and weeks 5-17 is the pseudoglandular stage, which is carnegie stage 22 and above.

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

type 2 pneumocytes are not fully developed

Lab 7 Questions

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

undifferentiated sarcomere which is multinucleated and are formed by myoblasts fusing together

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

a) Suffered a spinal cord injury

muscle atrophy would occur over time

b) Took up marathon running

a change in the type of muscle fibers would occur: slow twitch to fast twitch fibbers

Lab 10 Questions

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

The Thyroid - will lead to neurological defects

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

impairment of the synthesis of thyroid hormone which in turn disrupts the regulation of of various aspects linked to neural development

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

around week 10

Peer Review

group 1

Group 1:

Your page is awesome! Good headings, tables, pictures and extensive reference list. The tables especially, I felt, helped break down the information in to blocks of information that were easier to swallow. As far as improvement goes, there isn’t that much to do except maybe nit-pick over formatting – ie: be more consistent with spacing etc.

group 2

group 3

group 4

group 5



Extra Stuff



Early zygote.jpg