15. Ear Development Flashcards
external ear
aricle, external acoustic meatus, external layer of TM
middle ear
three ossicles, internal layer of TM, middle ear cavity
internal ear
vestibulocochlear organ
innervation of the ear
- great auricular n.
- CN V3: auriculotemporal
- CN VII
- CN X: auricular branches
caused by abnormal migration of NCC
- skin tags
- anotio (no ear)
- microtia (small ear)
external auditory meatus
first pharygeal cleft 1 or pharyngeal groove 1
meatal plug
ectodermal cells that fill the meatus (disappear before birth)
innervation of meatus
CN V3 and CN IX
inner ear derived from what embryonic layer
ectoderm
components of the membranous labyrinth
- utricle (dorsal)
- endolymphatic duct and sac
- semicircular ducts and ampullae (lateral canal)
- macula of utricle
- saccule (ventral)
- cochlear duct
- ductus reunions
- macula of saccule, organ of Corti
function of ampullae
acceleteration
function of macula
gravity
function of Ogan of Corti
sound vibration
innervation of CN VIII
vestibular ganglion and spiral ganglion
produced by the stria vascularis
similar in content to the intracellular fluid
endolymph
*stored in endolymphatic sac
free passage from subarachnoid spacei nto the inner ear
similar in content to CSF
perilymph
*may come from filtration of blood in perilymphatic space
embryonic layer of membranous labyrinth
mesenchyme/NCC
Where is periplymph located?
- scala vestibuli
- scala tympani
Where is endolymph located?
scala media
Where is stria vascularis located?
within the ligaments that stabilize the organ of Corti
external auditory meatus
1st pharyngeal cleft / ectoderm
tubotympanic recess
1st pharyngeal pouch / endoderm
tympanic membrane
ectoderm, mesoderm, and endoderm
malleus and incus
pharyngeal arch 1 (NCC)
