MODULE 7- ARPIN STUDY GUIDE Flashcards
movement of stereocilia toward kinocilium depolarizes/hyperpolarizes the hair cell
depolarizes
movement of stereocilia away from the kinocilium depolarizes/hyperpolarizes the hair cell
hyperpolarizes
what occurs from some tonic release of neurotransmitter in the absence of stimulation
baseline firing rate in vestibular nerve
otolith organs
-utricle
-saccule
what are otolith organs sensitive to
-linear accelerations
-head tilt
where are hair cells located
the macular
how is utricle macular oriented
horizontally
how is saccule macular oriented
vertically
striola
divides hair cells with opposite polarity
what displaces the hair bundles, causing depolarization + hyperpolarization
shearing motion between the otolithic membrane + the macular
what causes shearing motion
linear acceleration
-during increasing/decreasing velocity
-not constant velocity
what also causes shearing motion
head tilt
what are semicircular canals sensitive to
rotational/angular acceleration
-NOT linear/translational movements of the head
where is hair cell located
ampulla
hair bundles extend out into where
cupula
what is displaced during angular rotation
cupula
-causing displacement of hair bundle
how do semicircular canals work
in pairs
yaw rotation
head rotation to the right excites the right horizontal canal + inhibits the left horizontal canal
VOR
vestibulo-ocular reflex
what does VOR allow
function to stabilize gaze
VOR- head rotation sensed by semicircular canals leads to eye rotation in what direction
opposite direction
VOR ex- head rotation to the right
greater firing rate in right horizontal canal compared to left horizontal canal ->
activation of left lateral rectus + right medial rectus ->
both left + right eyes move to the left
what is VOR impacted by
unilateral vestibular deficits
VCR
vestibulocervical reflex
what tract does VCR involve
medial vestibulospinal tract
VCR- neck muscles are activated in response to what
head pitch rotation
VSR
vestibulospinal reflex
what tracts does VSR involve (2)
lateral + medial vestibulospinal tracts
how does VSR work
inputs from otolith organs activates ipsilateral antigravity muscles
