11-13. Auditory system Flashcards
The stapes converts pressure waves in air to fluid via the:
oval window
where is the basilar membrane?
cochlear
what do we use for detecting linear acceleration?
saccule
which responds best to movements in the horizontal plane? utricle or saccule?
utricle
where would you find the otolith crystals?
ototholic gelatinous membrane
what nerve carries sensory info from the otolith organs?
CN VIII
definition of sound
audible variations in air pressure
what is intensity
the amplitude of a wave - the difference in pressure between compressed and rarefied pathed of air in a sound wave.
what does intensity determine?
loudness
what is frequency?
The number of waves per second (Hz)
what does frequency determine?
pitch
name of external ear
auricle
channel from external ear to tympanic membrane
external acoustic meastus
what separates the outer and middle ear?
tympanic membrane
is the middle ear fluid or air?
air
names of 3 auditory ossicles?
malleleous, incus, stapes
what does the stapes hit ?
oval window
trunk of the cochlear
vestibule
what is at the end of the vestibule?
semi-circular canals
what occurs in the infection of the middle ear?
fluid builds up which prevents the movement of the auditory ossicles
where is the receptor organ for hearing?
cochlear
name of receptor organ for hearing?
spiral organ of Corti
what does the spiral organ of Corti contain?
hair cells
name 2 muscles of middle ear
tensor tympani
stapedius
describe the attenuations reflex
the contraction of the ear muscles in respond to a loud noise. this prevents movement of the ossicles to avoid damage to the oval window.
what can cause conductive hearing loss (2)
- scar tissue from infection
2. otosclerosis (proliferation of bone tissue)
describe the process of sound in the basilar membrane in steps
- pressure changes move oval window
- moves perilymph in scala vestibuli
- move reissner’s membrane
- moves endolymph in scala media
- causes vibrations in the basilar membrane
where are high freq located on the basilar membrane?
at the base
3 spaces in the inner ear
- scala vestibuli
- scala media
- scala tympani
name of fluid in
- scala vestibuli + tympani
- scala media
- perilymph
2. endolymph
name of membrane which is below the scala vestibuli
reissner’s membrane
which 2 membranes do the hair cells of the organ of corti lie?
basilar and tectorial
function of vestibular system
balance and movement
2 otolith organs
utricle and saccule
name the 3 semicircular canals
anterior, posterior, horizontal
what type of acceleration do the ototlith organs detect?
linear
what type of acceleration do the semi-circular canaals detect?
angular/ rotational
what are the semi-circular canals filled with?
endolymph
what type of movements do the … detect?
i) utricle
ii) saccule
i) horizontal
ii) vertical
which 2 layers do the hair cells lie between?
otolith gelatinous membrane and the macula membrane
what is contained within the otolith membrane?
otolith crystals
function of otolith crystals
allows a change in density of the membrane when we move - giving info about our orientation
what is the ampulla?
swelling at base of semi-circular canals which contain the hair cells
what is the cupula?
gelatinous membrane which contains sensory processes (hairs)
movement of the stereocilia towards the kinocilium leads to opening or closing of the tip links?
opening
what does the opening of the stereocilia links lead to in terms of K+ and depolarisation?
K+ influx into cell, depolarisation
bending sterocilia away from the kinocilium leads to what?
reduced Ca2+ influx - below baseline rate
Rotation of the head to the left will reuslt in activation of which horizontal canal; right or left?
left
for a sound of 300Hz , which auditory processing would be used?
Both tonotopy and phase locking
If a 6kHz sound came from the left side of the body what would we see;
a) Excitation in right MSO
b) Excitation in left MSO
c) Excitation in right LSO
d) Excitation in left LSO
d)Excitation in left LSO
A person is turned to the left for 30 seconds (spinning). what would we see immediately after the rotation stops? saccadic (fast) movements of the eye to the right or the left?
which way is the endolymph turning at this point?
right as endolymph is moving to the left
