Pharyngeal Pouches and Clefts B&B Flashcards
match: ectoderm/endoderm with pharyngeal cleft/pouch
pharyngeal pouches are on the interior - endoderm
pharyngeal clefts are on the exterior - ectoderm
what is derived from the 1st pharyngeal pouch?
inner ear structures - Eustachian tube, middle ear cavity, contributes to tympanic membrane
from which pharyngeal pouch is the Eustachian tube derived?
1st pharyngeal pouch
what is derived from the 2nd pharyngeal pouch?
lining of the palatine tonsils in the back of the throat
2nd pouch forms buds which are invaded my mesoderm and lymphatic tissue
from which pharyngeal pouch are the palatine tonsils derived?
2nd pharyngeal pouch - forms buds which are invaded my mesoderm and lymphatic tissue
what is derived from the 3rd pharyngeal pouch?
thymus (mediastinum) and inferior parathyroid glands (neck)
dorsal wings of pouch become parathyroid, ventral wings of pouch become thymus
from which pharyngeal pouch are the thymus and inferior parathyroid glands derived?
3rd pharyngeal pouch - dorsal wings of pouch become parathyroid, ventral wings of pouch become thymus
what is derived from the 4th pharyngeal pouch? (2)
- superior parathyroid glands
- ultimobranchial body - incorporates into thyroid gland and forms C-cells (calcitonin), which are derived from neural crest cells
dorsal wings forms parathyroid, ventral wings forms ultimobranchial body
from which pharyngeal pouch are the superior parathyroid glands and ultimobranchial body derived?
4th pharyngeal pouch - dorsal wings forms parathyroid, ventral wings forms ultimobranchial body
ultimobranchial body - incorporates into thyroid gland and forms C-cells (calcitonin), which are derived from neural crest cells
what is the major structure derived from the 1st - 4th pharyngeal pouches?
1st —> Eustachian tube
2nd —> palatine tonsils
3rd —> thymus + inferior parathyroid glands
4th —> ultimobranchial body (C-cells) + superior parathyroid glands
what is derived from the 1st - 4th pharyngeal clefts?
1st —> external auditory meatus
2nd, 3rd, 4th —> cervical sinus (temporary cavity)
what develops from the 1st pharyngeal cleft?
external auditory meatus
what type of branchial cleft cyst is most common? where would it be located?
aka cyst of embryonic pharyngeal cleft - 2nd cleft cysts are most common, located anterior to sternocleidomastoid
do not move with swallowing! (in contrast to thyroglossal duct cyst)
if a child presents with a neck mass, how can you differentiate a branchial cleft cyst from a thyroglossal duct cyst?
branchial cleft cysts (pharyngeal cleft) DO NOT MOVE with swallowing
thyroglossal duct cysts will move with swallowing
what is the most common craniofacial malformation?
cleft lip, often occurs with cleft palate
