Third to 8th weeks Development

Question 1

What does the ectoderm form?

Answer 1

CNS/PNS
sensory epithelium
epidermis
glands and teeth enamel

Question 2

What induces neurulation?

Answer 2

the appearance of the notochord and the prechordal mesoderm causes the ectoderm to form the neural plate

Question 3

What is the process of neurulation?

Answer 3

neural folds become elevated and grow toward each other and fuse at midline; the fusion proceeds cranially and caudally and forms the neural tube that stays open until days 25 and 27

Question 4

How is the neural crest formed?

Answer 4

cells on the lateral edges of the neural plate dissociate and undergo an epithelial-to-mesenchymal transition as they leave the neuroectoderm by active migration

Question 5

What induces neural crest formation?

Answer 5

BMP

Question 6

What do neural crest cells form?

Answer 6

connective tissue and bones of face/skull
cranial nerve ganglia
C cells of the thyroid gland
Conotruncal septum of the heart
Odontoblasts
dermis in face/neck
dorsal root ganglia
sympathetic chain ganglia/ preaortic ganglia
parasympathetic ganglia of the GI tract
adrenal medulla
schwann cells
glial cells
meniges of the forebrain
melanocytes
smooth muscle cells of blood vessels in face/forebrain

Question 7

What does the somatic/parietal mesoderm form?

Answer 7

lateral and ventral body wall, membranes that line pleural, pericardial, and peritoneal cavities

Question 8

What doe the splanchnic/visceral mesoderm form?

Answer 8

wall of the gut

Question 9

What does the intermediate mesoderm form?

Answer 9

urogenital structures

Question 10

What does the paraxial mesoderm become?

Answer 10

somites, vertebrae, ribs, muscles, and dermis

Question 11

What is vasculogenesis?

Answer 11

Where vessels arise from blood islands

Question 12

What is angiogenesis?

Answer 12

where vessels arise by sprouting from existing vessels

Question 13

What are hemangioblasts?

Answer 13

precursor cells (from mesoderm) for vessel and blood cell formation that are induced by vascular endothelial growth factor (VEGF)

Question 14

What is the main thing derived from the endoderm layer?

Answer 14

GI tract (folding) but also:
epithelial lining of the respiratory tract, urinary bladder, tympanic cavity, and auditory tube, parenchyma of the thyroid, parathyroids, liver, and pancreas, and reticular stroma of the tonsils and thymus

Question 15

What is the vitelline duct?

Answer 15

how the midgut temporarilly communicates with the yolk sac