embryology - back

Question 1

role of the notochord?

Answer 1

provides rigidity
defines cranio-caudal axis
induces overlying ectoderm to form neuroectoderm and neural plate

Question 2

what does the notochord ultimately become?

Answer 2

nucleus pulposus

Question 3

what is the result of a notochord that wrongfully remains?

Answer 3

becomes a malignant tumor –> chordoma

Question 4

steps for formation of neural tube:

Answer 4

1. notochord and next door paraxial mesoderm (somite) induce overlying ectoderm to form thick neural plate
2. lateral margins of plate become elevated (neural folds) with neural groove in between
3. folds come together and groove becomes tubular
4. margins of folds unite, forming a tube
5. surface ectoderm becomes continuous across dorsal surface, tube migrates below
6. neural crest cells migrate dorsolaterally

Question 5

what are some derivatives of neural crest cells?

Answer 5

-connective tissue
-cranial nerve ganglia
-dorsal root ganglia
-sympathetic chain
-schwann cells
-glial cells
-LEPTOMENINGES (pia and arachnoid mater)