Embryology of the Ear Flashcards
cristae ampullaris
in the ampulla of each semicircular canal
macula
one in the utricle and one in the saccule
cochlear
numerous along the cochlear duct
what is the thickening of ectoderm called during the fourth week of development
ecotderm
the otic placode forms __________ and then _______
otic placode and vesicle
_________gives rise to the membranous labyrinth
otic vesicle
the otic vesicle forms what two structures
utricle and saccule
the utricle forms
endolymphatic duct, utricle and semicircular canals
the saccule forms
the saccule and cochlear duct
the _____________ is related to the cochlear duct and is involved in hearing
spiral ganglion
the ____________is involved in detection of movement of the head
vestibular ganglion
the ganglia form from
neural crest cells
the otic capsule helps also form what skull bone
petrous part of the temporal bone
what is the space called within the otic capsule
perilymphatic space
what is the fluid within the perilymphatic space called
perilymph
_________can cause malformation of the cochlea and deafness
rubella infection
what is the significance of the perilymphatic space and the cochlear duct
it is related to it twice (once above and once below)
What are the two space of the perilymphatic space called
scala tympani and scala vestbuli
what helps form the tympanic membrane
the first pharyngeal groove
what is the pouch lined with
endoderm
what is the groove lined with
ectoderm and mesenchyme
what germ layers is the tynmpanic membrane derived from
ecto, endo, meso (all three!)
the 1st pharyngeal pouch helps form
the middle ear which is continuous with the mastoid antrum and nasopharynx ia pharyngotympanic tube (auditory tube)
what are the three middle ear ossicles
malleus, incus, and stapes
malleus and incus are derived from
1st pharyngeal arch
stapes is derived from
cartilage of the second arch
tensor tympani m is attached to ________and is derived from ________arch
malleus; mesenchyme of first arch
the tensor tympani is innervated by
CN V
stapedius is innervated by
facial nerve
external ear develps at the crossroads of
1st and 2nd pharyngeal arches
what is anotonia
absence of an ear
what is microtia
small ear
auricular appendages
persistence of auricular hillocks
what dis microtia result from
absence of auricular hillocks and is characterized by the absence of the auricle; this defect is associatied with other defects
___________-are small depressions located anterior to the auricle
preauricular sinuses
preauricular sinuses are the result from
abnormal closure of the first pharyngeal groove
what happens when the plug of cells in front of the tynpanic membrane fail to regress
atresia of external auditory meatus occurs
__________is when epidermoid tissue is within the tympanic membrane
congenital cholesteatome
congenital fixation of the stapes
Complete absence of the annular ligament of the stapes without evidence of otosclerotic bone growth may be congenital stapes fixation.
