Physio of Auditory & Vestibular System Flashcards
The basilar membrane is _____ and _____ near the oval and round windows.
narrow and stiff
The basilar membrane is _____ and _____ near the helicotrema.
wide and flexible
High frequency sounds deflect at the _____ part of the basilar membrane.
base/oval window
Low frequency sounds deflect at the _____ part of the basilar membrane.
apex/helicotrema
____ is where distinct locations of the basilar membrane interpret discrete frequencies. This is analogous to ____.
Tonotopy; somatotopy
The vibration of the basilar membrane creates a _____ ______ of the cochlea.
pressure differential
The pressure differential of the cochlea results in a ______ ______ against the stationary tectorial membrane.
shearing force
The shearing force of the tectorial membrane causes displacement of the …….
stereocilia of the outer hair cells.
The inner hair cells are activated by …….
fluid movement in the cochlear duct.
Depolarization of the cell occurs when _____ _____ open at the apex of the stereocilia.
cation channels
Stereocilia are connected to each other via tip links that transmit force to an elastic gating spring, which, in turn, opens the ____ ____.
TRPA1 channels
TRPA1 channels are _______ channels.
mechanotransduction
Endolymph is potassium-____.
RICH
Endolymph fills the ____ ____ and _____ _____.
cochlear duct and membranous labyrinth
Endolymph bathes the ……
apical end of the hair cells.
Endolymph is found in the ____ ____.
scala media
Endolymph is made by the _____ _____.
stria vascularis
Perilymph is potassium-____.
POOR
Perilymph bathes the ……..
basal end of the cochlear hair cells.
Perilymph is found in the ____ ____ and ____ ____.
scala vestibuli and scala tympani
The opening of cation channels on stereocilia will cause a rapid influx of ___ into the cell.
K+
Influx of K+ into the hair cell causes ____ of the cell.
depolarization
Depolarization of the hair cells causes ____ channels at the base of the cells to open.
Ca++
Calcium influx into the hair cell causes which neurotransmitter to be released into the synaptic cleft?
Glutamate
What does glutamate being released into the synaptic cleft cause?
Stimulation of the afferent cochlear nerve fibers and transmission of a signal to the CNS (sending info to the tracts).
An upward displacement of the basilar membrane creates a shearing force that results in _____ _____ of the stereocilia.
lateral displacement
Lateral displacement of the stereocilia causes _____ of the hair cell.
depolarization
A downward displacement of the basilar membrane creates a shearing force that results in ______ of the hair cell.
hyperpolarization
The high endocochlear potential (+80 mV) serves to drive positively charged ions into the hair cell ___ their concentration gradient.
down
The endocochlear potential forms the ____ ____.
blood-labyrinth barrier (BLB)
____ ___ and ___ ___ disrupt the stria vascularis by diminishing its endocochlear potential, thus impacting hearing.
Ototoxic drugs; carbon monoxide
Inner hair cells are the primary source of ____ ____.
auditory information
How many layers do inner hair cells have?
one
___ hair cells synapse at the peripheral terminal of a primary afferent sensory neuron.
Inner
___ hair cells are the primary cells that amplify sound waves that results in the movement of the basilar membrane.
Outer
Outer hair cells’ contractile properties allow them to act like an ______.
amplifier
How many layers do outer hair cells have?
three
____ hair cells synapse with sensory afferent peripheral terminals in the spiral ganglions, as well as with terminals from efferent neurons.
Outer
What is being tested in a newborn hearing screening test? What does this screen for?
otoacoustic emissions; sensorineural hearing loss
Otoacoustic emissions originate in the ____ _____ _____ and are known as _______ ______.
superior olivary complex; olivocochlear efferents
Medial olivary complex neurons innervate ___ hair cells.
outer
Lateral olivary complex neurons innervate ___ hair cells.
inner
___ efferents:
1) reduce electromotility of outer hair cells
2) decreases basilar membrane motion
3) reduces responses of inner hair cells and auditory nerve fibers
Olivocochlear
____ efferents:
1) tensor tympani to the malleus and the TM
2) stapedius to the stapes (from CN VII)
3) attenuates sound
4) bilateral response to high sound levels
5) contractions decrease transmission of sound
6) act at low frequencies
7) may prevent damage
Medial ear
What efferent is implicated in tinnitus?
medial ear efferents
___ efferents:
1) arise from the CN VIII
2) sympathetic adrenergic fibers
3) regulates vascular tone in blood supply to cochlea
Autonomic
____ cochlear nuclei integrate the acoustic info with somatosensory info.
Dorsal
___ cochlear nuclei begin processing the temporal and spectral features of the sound (time and spectrum).
Ventral
Medial and lateral superior olivary complexes receive ____ ____.
Glutamatergic (excitatory) input
The ___ generates a map of interaural TIME differences.
MSO
The ___ generates a map of interaural INTENSITY differences.
LSO
The ____ _____ suppresses info related to echoes and arrives at a final estimation of localization of sounds along the horizon.
inferior colliculus
Info about time and intensity differences of sound converge to the _____ _____.
inferior colliculus
The ____ ___ takes the location data from the inferior colliculus and adds vertical height to create a spatial map of the sound’s location.
superior colliculus
The ____ _____ ____ processes features of speech inflections.
medial geniculate nucleus
The ______ ______ _____ does conscious perception of sound; higher order processing of sounds (loudness, changes in volume, rate of frequency changes)
primary auditory cortex
The ____ ____ ____ responds to more complex sounds (music), identifying/naming a sound, and human speech.
auditory association cortex
Is the auditory association cortex tonotopic?
No
How does a cochlear implant work?
It has an internal and external component. The internal component includes a receiver and an electrode trave. The receiver decodes the signal and delivers the electrical signals to the electrode array. The electrode array sits in the cochlear duct along the afferents from CN VIII. Electrical signals anywhere along the electrode array will stimulate a particular cochlear nerve afferent along the basilar membrane, mimicking the tonotopy of it.
What does rotation in the vertical plane forwards (falling forward) maximally activate?
anterior semicicular canal
What does rotation in the vertical plane backwards (falling backward) maximally activate?
posterior semicircular canal
What does rotation in the horizontal plane (spinning) maximally activate?
horizontal semicircular canal
What does linear acceleration forward and backward (walking/running) maximally activate?
utricle
What does linear acceleration up and down (jumping) maximally activate?
saccule
