pharyngeal pouches/ pharyngeal grooves/clefts and membranes

Question 1

numbering

Answer 1

pharyngeal clefts and pouches are caudal to the arch of the same number

Question 2

pharyngeal cleft

Answer 2

is the outside

Question 3

pharyngeal pouch

Answer 3

inside

• formed by the endoderm of the pharynx
• each pouch forms a diverticulum of epithelium

Question 4

diverticulum

Answer 4

pouch or sac that branches out from a hollow organ

Question 5

1st pharyngeal pouch

Answer 5

• distal portion expands to form the epithelial lining of tympanic cavity and mastoid atrium
• proximal narrow portions forms the lining of the auditory tube

Question 6

2nd pharyngeal pouch

Answer 6

• lining become the surface epithelium of the palatine tonsil
• a part of the pouch remains as the tonsillar fossa

Question 7

3rd pharyngeal pouch

Answer 7

• dorsal region: inferior thyroid gland

- vental regions: forms the stroma of the thymus

Question 8

4th pharyngeal pouch

Answer 8

• dorsal region: forms the glandular cells of the superior parathyroid gland
• ventral region: forms ultimobranchial body (cells of the ^body incorporate into the thyroid gland as the parafollicular cells)

Question 9

1st pharyngeal cleft

Answer 9

forms the epithelial lining of the external auditory meatus

Question 10

pharyngeal membrane 1

Answer 10

tympanic membrane

Question 11

cysts

Answer 11

• remnants of the cervical sinus, usually below the angle of the jaw
• always lateral, usually found along the border of the SCM

Question 12

fistulas

Answer 12

occur when the 2nd pharyngeal arch fails to grow caudally over the 2nd, 3rd, and 4th arches, leaving the clefts in contact with the surface of the epithelium by a narrow canal

Question 13

brachial cleft cyst

Answer 13

• cysts have a thin wall, contain turbid fluid and re lined by stratified squamous or respiratory type epithelium
• below the angle of the jaw along the border of the SCM