Neuro Vestibular System Flashcards
What are the two components of the otolith organ?
1) utricle
2) saccule
The neuroepithelium of the otolith organ is what? What are otoliths?
macula. otoliths are “ear stones” embedded in the macula
What is the crista ampullaris?
it is the neuroepithelium of the semicircular canal. Note that the capula “floats” in endolymph
The membranous labyrinth is filled with _____, and the membranous labyrinth is suspended with in the ______-filled osseous labyrinth
endolymph
perilymph
The ____ labyrinth is sensitive to vibrations from 0-1 Hz
static
What else is the static labyrinth sensitive to besides vibrations from 0-1 Hz?
linear acceleration (gravity)
What are the otoliths of the static labyrinth embedded in?
the gelatinous macula
The dynamic labyrinth consists of ____ pairs of semicircular canals
3
The canals of the dynamic labyrinth sense what?
turning movements of the head
The dynamic labyrinth is sensitive to vibrations of what hertz?
1-10 Hz
What do canals of the dynamic labyrinth respond to?
angular acceleration
What is the primary function of the dynamic labyrinth?
provide reflex control of eye movements. When the head turns in one direction, the eyes turn in the opposite direction
What part of the semicircular canals detects when the head turns?
The endolymph does not do the detection. The capula of the crista ampullaris detects when the head turns. The afferent fibers fire, signaling that the head is turning
When deflected toward the ______, the hair cells of the horizontal semicircular canals increase their firing rate
midline
When the head turns, the ____ on one side deflects toward the midline and the hair cell firing rate on that side increases
cupula
When the head turns Right, the cupula on the Right deflects ______
medially
When the cupula is directed medially, the ____ on the right increases its firing rate
crista ampullaris
When the crista ampullaris fires, the eyes respond via the _______ connections to deflect tothe left
vestibulo-ocular
The doll’s eye response involves stimulation of _______ and ______ and is seen in young infants and people in coma
semicircular canal and otolith
What are the three ascending projections of the vestibular system?
1) medial longitudinal fasciculus
2) pontine tegmentum
3) cerebellum (eye movement control)
What is the descending projection of the vestibular system?
spinal cord (control of antigravity muscles)
What is nystagmus?
eyes reach the limit of their orbital movement and then suddenly reset to their rest position. The result is an oscillating eye movement. The slow component is vestibular and the fast component is reset
What does COWS mean in the context of the caloric test for nystagmus?
COWS - cold, opposite, warm, same
Where is the vestibular cortex located?
posterior insular cortex
