Embryology Flashcards
What does the first pharyngeal arch become?
External ear
What is a pharyngeal pouch and arch?
Pouch is in the inside, while arch is on the outside
What does the first pharyngeal pouch become?
Internal ear
What do archs 2, 3, 4 become?
Degenerate, or become a cystic remnant
What happens to pharyngeal arch 5?
Never develops in humans
What happens to pharyngeal pouch 2?
Becomes the pouch for the tonsils
What happens to pharyngeal pouch 3? (2 parts)
- Develops into the inferior parathyroid gland
- Thymus
What happens to pharyngeal pouch 4?
Develops into the superior parathyroid gland
What are the pharyngeal membranes?
Thin membrane between each arch
What does the first pharyngeal membrane form?
TM
What do pharyngeal membranes 2, 3, and 4 form?
Degenerate
What structures are formed from the neural crest cells of pharyngeal arch 6?
laryngeal cartilage
What is the role of the Sonic hedgehog gene in development?
Patterning along anterior posterior axis
What is the role of the Wnt-7 gene in development?
Organization along dorsal-ventral axis
What is the role of the FGF gene in development?
Stimulates mitosis of underlying mesoderm to lengthen limbs
What is the role of the Hox gene in development?
Segmental organziation of embryo in a craniocaudal direction
Mutations lead to appendages in wrong locations
Appendages in wrong locations = which gene mutation?
Hox
What are the components of the VACTERL association?
Vertebral abnormalities Anal atresia Cardiac defects TE fistulas Renal defects Limb defects
What is the embryological derivative of the nucleus pulposus?
Intervertebral discs
What is the teratogenic effect associated with: alkylating agents
absence of digits
What is the teratogenic effect associated with: aminoglycosides
CN VIII defects (“A mean guy hit a baby in the ear”)
What is the teratogenic effect associated with: carbamazepine
NTD
What is the teratogenic effect associated with: folate antagonists
NTDs
What is the teratogenic effect associated with: Li
Ebstein cardiac anomaly
