HEARING PT. 2 Flashcards
what communicates volume and pitch of sound
frequency of APs being sent tells how loud and
location of activation on basilar membrane tells what pitch
where is the cochlear hair located
on top of basilar membrane
what do the outer hair cells protect and increase
» Protect inner hair cells from damage
» Increase responsiveness of inner hair cells
what do the inner hair cells participate in
sound transduction
how do the inner hairs protrude
protrude from top (arranged from longest to shortest)
describe tip links of basillalr hairs
inner hair cells are Bound together by tip links, which are connected to mechanically gated ion channels
Pulling tip links opens ion channels
how does sound transduction work
basilar membrane deflected
covers of tip links on hair cell open
hair cells depolarized
send signal to brain
how are pitch and volume determined by sound wave itself
pitch determined by frequency of wavelength and volume is determined by amplitude
of waves.
how are pitch and volume interpreted in brain
our brain gets pitch info from where basilar membrane was vibrated
and volume info from frequency of action potential to brain
why do loud sounds cause damage to eardrum
ouder sound = more deflection of basal membrane
causes damage because deflection can be so great that it rips hair off hair cells
how do we localize sounds
depends on relative intensity and relative timing of sound waves reaching both ears
whats conduction deafness
when something hampers sound conduction to the fluids of the internal ear
» Impaction of ear wax, perforated eardrum
whats sensorineural deafness
results from damage to the neural structures at any point
» Usually gradual loss of hair cells from single very loud noise or prolonged loud noise
» Tears hair off hair cells
whats tinnitus
ringing, buzzing, or clicking sound in ears in absence of auditory stimuli » Destruction of some neurons of the auditory pathway
whats menrie’s syndrome
labyrinth disorder affecting all of the internal ear » Equilibrium is off, finding balance is hard, vertigo, nausea
what are the two regions in the vestibular appartus
vestibule and semicircular canals
what does the vestibule contain and what receptors does it house
Contains saccule (extends to cochlea) and utricle (extends to semicircular canals)
Houses equilibrium receptors: respond to gravity pull and head position change
what do the semicircular canals contain and what receptors do they house
Contain semicircular duct (communicates with utricle)
House equilibrium receptors in ampulla (swelling): respond to rotational head movement
what does the maculae monitor, play a key role in, and respond to
Monitors static equilibrium
» Plays key role in control of posture
» Responds to linear acceleration forces (not rotational)
what are the two maculaes called
utricle and saccule
what does the utricle maculae respond to and what is it stimulated by
Respond to change along a horizontal plane, such as tilting your head
Stimulated by forward/backward movements
what does the saccule maculae respond to and what it is stimulated by
Respond to changes along a vertical plane
Stimulated by up/down movements
does the maculae have hair cellls
yes, stereo cilia that are embedded in a otolith (stone) membrane
what do the hair cells do for membrane
give it weight and increases inertia
what happens if the stones fall out of otolith membrane
causes inertia
what does the Cristae Ampullares monitor and respond to
Monitors dynamic equilibrium
» Responds to rotational forces
how is the crust ampullares activated
Endolymph (inside membrane of the labyrinth) articulates with the Crista receptors
Bends hairs causing depolarization and increases afferent impulses to the brain
BASICALLLY, WHEN YOU ROTATE, HAIRS FLOP IN A CERTAIN DIRECTION
