Exam 5: Fourth Week: Forming the Embryo

A researcher ablates (removes) the neural folds of an animal embryo prior to formation of neural crest cells.What structure might not develop depending on the exact level removed?

A researcher overexpresses the actin-binding protein Shroom in the surface ectoderm.What change in the ectodermal cells would this overexpression cause?

Omphalocele and gastroschisis are examples of which type of birth defect?

A researcher inactivates a gene that affects the dorsal-ventral patterning of the neural tube.Which gene product is known to play such a role?

A first-year surgery resident sees a child with a skin-covered neural tube defect.The chief resident says that the defect was caused by abnormal secondary neurulation.Assuming this is true,at what level of the CNS would the defect occur?

The inner tube of the tube-within-a-tube body plan gives rise to which structure?

A major tissue movement involved in neurulation is convergent extension.What signaling pathway plays an essential role in convergent extension?

A researcher overexpresses the transcription factor Slug in the surface ectoderm.What change in the ectodermal cells would this overexpression cause?

A researcher knocks out a gene that is expressed in the mouse embryo during neurulation stages,but this gene is never expressed in the neuroepithelium (neural plate or neural tube).Hence,she is surprised when the resulting embryos form neural tube defects.What is the explanation for this?

A woman has a child with spina bifida aperta.She is planning to have another child and is concerned that the second child will also have spina bifida aperta.What should her physician advise her to take daily to reduce the chances that the second child will have spina bifida aperta?