Branchial Cleft and Pouch Derivatives

Question 1

External auditory meatus

Answer 1

1st cleft (ectoderm)

Question 2

Temporary cervical sinuses, eventually obliterated

Answer 2

2nd thru 4th clefts (ectoderm)

Question 3

Persistent cervical sinus

Answer 3

Branchial cleft cyst within the lateral neck

Thyroglossal duct cysts are found medially

Question 4

Middle ear cavity, Eustachian tube, mastoid air cells

Answer 4

1st pouch (endoderm structures of the ear)

1. Ear
2. Tonsils
3. Bottom-To = Bottom parathyroid + Thymus
4. Top = Superior parathyroid

Question 5

Epithelial lining of the palatine tonsil

Answer 5

2nd pouch

1. Ear
2. Tonsils
3. Bottom-To = Bottom parathyroid + Thymus
4. Top = Superior parathyroid

Question 6

Dorsal wings - inferior parathyroids

Ventral wings - thymus

Answer 6

3rd pouch - 3 structures

1. Ear
2. Tonsils
3. Bottom-To = Bottom parathyroids (2) + Thymus
4. Top = Superior parathyroid

Question 7

Dorsal wings - superior parathyroids

Answer 7

4th pouch

1. Ear
2. Tonsils
3. Bottom-To = Bottom parathyroid + Thymus
4. Top = Superior parathyroid

*Note that parafollicular C cells from neural crest