Branchial Pouch Derivatives

Question 1

1st pouch

Answer 1

Ears: middle ear cavity, Eustachian tube, mastoid air cells

Question 2

2nd pouch

Answer 2

Tonsils lining

Question 3

3rd pouch

Answer 3

3 structures:
Thymus
Left and right inferior parathyroid

Question 4

4th pouch

Answer 4

Superior parathyroids

Question 5

Mnemonic

Answer 5

Ear, tonisils, bottom-to-top: 
1 (ear)
2 (tonsils)
3 dorsal (bottom for inferior parathyroid) 
3 ventral (to=thymus) 
4 (top=superior parathyroids)

Question 6

DiGeorge Syndrome

Answer 6

Failure of 3rd and 4th pouches to develop
T-cell deficiency (thymic aplasia)
Hypocalcemia (failure of parathyroid development)
Associated with cardiac defects

Question 7

Men 2A

Answer 7

Mutation of Germaine RET (neural crest cells):
Pheochromocytoma (adrenal medulla)
Parathyroid (tumor)
Parafollicular cells (medullary thyroid cancer)

Question 8

Cleft lip

Answer 8

Failure of fusion of the maxillary and medial nasal processes (formation of primary palate)

Question 9

Cleft palate

Answer 9

Failure of fusion of the two lateral palatine processes or
Failure of fusion of lateral palatine processes with nasal septum and or median palatine process (formation of secondary palate)