Auditory

penna and external auditory meatus/canal does what

collects sound to transmit to tympanic membrane

what is the outer ear innervated by for sensory

CN VII

tympanic membrane role

vibrates in response to sound waves

turns sound waves into mechanical stimulus

how does the tympanic membrane transmit sound waves to mechanical 

pushes against malleus, incus, and stapes 

ossicles

malleus, incus, stapes

what happens if the ossicles are damaged

causes conductive hearing loss

what does the ossicles do

transmit vibrateions from tympanic membrane to the inner ear

what are the accessory muscles in the ear

tensor tympani and stapedius

what do the accessory muscles do

contract to dampen vibrations and protect against loud noises, mask own voice

what is the stapedius innervated by

CN VII

what is the tensor tympani innervated by

CN V

eustachian tube

connects middle ear with the pharynx

equalizes pressure ni the middle ear

what is the inner ear filled with

perilymph

oval window

where the stapes convert bony vibration to a fluid wave inside the cochlea

starts the fluid wave

what chambers are within the cochlea

scala vestibuli
scala tympani
scala media

what is the scala vestibuli and scala tympani filled with 

perilymph

what is the scala media filled with

endolymph

vestibular (reissner’s) membrane

roof of the scala media

basilar membrane

bottom layer of scala media

stores organ of corti

organ of corti

organ of hearing

translates fluid wave into electrical impulses via stereocilia

transmission of sound

tympanic membrane → ossicles → oval window (stapes) → scala vestibuli → scala tympani → scala media → tectorial and basilar membrane → organ of corti → cochlear nerve

spacial localization

determined by the difference in time arrival of sound between the two ears and the sound pressure difference between the two tympanic membranes

which organ of corti gets stimulated first

primary sensory afferents of peripheral pathway synapse in

dorsal and ventral cochlear nuclei at pontomedullary junction

dorsal cochlear nucleus

crosses right away and travels up in the lateral lemniscus until it hits the inferior colliculus in midbrain

carries hight frequency pitches

ventral cochlear nucleus

splits right away

carry low frequency pitches

peripheral hearing loss is due to

damage to nerve or inner hair cells

auditory radiations project from the thalamus to

primary auditory cortex (temporal lobe)

auditory problems are mostly __

unilateral / peripheral issues

cortical processing

primary auditory cortex sends fibers to auditory association in temporal lobe, insular cortex, and parietal operculum 

gives interpretation and meaning to sound

auditory association cortex damaged leads to

inability to give meaning to sounds (auditory agnosia)

bilateral damage to cortex would lead to

cortical deafness

if able to hear sounds they would not be able to interpret 

damage to CN V would

dampen sound due to damage to tensor tympani

damage to CN VII would cause

dampening of sound due to damage to stapedius

what is CN VIII reflex pathway for

modulate sensitivity of stereocilia

reflex pathway of CN XI

head turning in response to sound

conduction deafness

caused by external auditory canal or middle ear abnormalities

hearing aid is used

what is a peripheral problem of hearing loss

anything within the cochlea along CN VIII

nerve deafness

unilateral lesion of cochlear nerve or organ of corti

cochlear implant used

cause is viral agents or drugs

tinnitus

ringing in ears

caused by damage to cochlea or auditory cortex

hyperacusis

hypersensitivity to sound

results from loss of innervation to stapedius or tensor tympani

presbycusis

gradual impairment of ability to perceive or discriminate sounds

bilateral loss of high frequency 

acuity testing

rubbing fingers together to look for differences in sides
can you hear this 

rinne’s test

comparison of bone vs air conduction

normal is hearing air conduction louder 

if bone conduction is hear louder what does that mean

conductive hearing loss

weber’s test

tuning fork at top of head

normal is hearing equally on both sides

weber test lateralizes to unaffected ear and rinne test has air conduction louder

sensorineural hearing loss

audiogram has reduced bone and air conduction

sensorineural hearing loss

weber test lateralizes to affective ear and rinne test has bone conduction louder

conductive hearing loss

weber is louder on the right side and rinne test has air louder on the right side

sensorineural on the L