Branchial Pouches

Question 1

Branchial 1st pouch derivative

Answer 1

Ear: contributes to endoderm lined structures of the ear - middle ear cavity, eustachian tube, mastoid air cells

Question 2

Branchial 2nd pouch derivative

Answer 2

Epithlial lining of the palatine tonsils

Question 3

Branchial 3nd pouch derivative

Answer 3

Dorsal wing - inferior parathyroid ventral wing - thymus

Question 4

Branchial 4th pouch derivative

Answer 4

Dorsal wings - develops in superior parathyroids

Question 5

Digeorge syndrome

Answer 5

Abnormal development of 3rd and fourth pouches - T cell deficiency (thymic aplasia) and hypocalcemia (parathyroid underdevelopment). A/w cardiac defects (conotruncal abnormalities)

Question 6

MEN2A

Answer 6

Mutation of germline RED (neural crest cells). Adrenal medulla (pheochromocytoma), parathyroid tumor: 3rd and fourth pharyngeal pouch, parafollicular cells (medullary thyroid cancer): derived from neural crest cells; a/w 4th and 5th pharyngeal pouches