Branchial pouch derivatives

Question 1

what layer do the branchial pouches come from?

Answer 1

Endoderm

Question 2

1st pouch develops into….?

Answer 2

Develops into:

• middle ear cavity
• eustachian tube
• Mastoid air cells

contributes to the endoderm-lined structures of the ear

Question 3

2nd pouch develops into….?

Answer 3

Develops into:

Epithelial lining of palatine tonsil

Question 4

3rd pouch develops into…?

Answer 4

Dorsal wing:
- develop into INFERIOR parathyroids

Ventral wing:
- develop into THYMUS

Question 5

4th pouch develops into…?

Answer 5

Dorsal wing: develop into SUPERIOR parathyroids

Question 6

Digeorge Syndrome

Answer 6

Aberrant development of 3rd-4th pouches
- no thymus or parathyroids

• T cell deficiency ( thyme aplasia) and hypocalcemia (failure of parathyroid development)
• cardiac defects (conotruncal anomalies: truncus arteriosis and Tetralogy of Fallot)