Flashcards in W04_03 Hearing Deck (24)
what range of frequencies do we hear?
20Hz - 20 kHz
speed of sound in air?
what kind of joints are at the auditory ossicles?
these can fuse in later years - less flexibility results in hard of hearing.
tensor tympani innervated by which CN?
V3 (T rigeminal)
stapedius innervated by which CN?
VII (S even)
what do you call the perception of loud sound due to lesion of V3 or VII?
middle ear connects to which cavity via eustacian tube?
fact: tympanic cavity connected to mastoid air cells.
the cochlea spirals around this bony core:
what are the three spaces in the cochlear cross section?
in the scala vestibuli/tympani is this fluid:
in the scala media is this fluid:
endolymph (high [K+])
endolymph is secreted by which structure?
stria vascularis (along lateral wall of scala media)
this bony protrusion extends from the modiolus into the cochlear space:
this opening connects the scala tympani and scala vestibuli:
the organ of corti is covered by and intimately connected to this:
what's another name for the organ of corti?
what type of neurons transmit sound sense from the cochlea?
fact: outer hair cells are connected to the tectorial membrane, while inner hair cells are not.
when the basilar membrane moves up, the stereocilia move this way:
this structure isolates endolymph from perilymph; is connected to hair cells
how does the transduction of sound energy convert to electrical energy via hair cells?
bending stereocilia opens K+ channels;
depolarization opens v-gated Ca2+ channels;
depolarization increase neurotransmitter release to axon.
even though outer hair cells outnumber inner hair cells 3:1, 95% of spiral ganglion neurons get inputs from IHCs. what do outer hair cells do?
amplify movement of basilar membrane, especially in low volume sound.