Flashcards in W03_07 Motor Control 4: Vestibular System Deck (22)
what reflex keep the eyes fixed during head movements?
what reflex keeps the head balanced during body movements?
what kind of organs are the utricle and saccule?
saccule detects motion in which plane?
utricle detects motion in which plane?
what is the fluid in the semicircular canals called?
what do you call the tallest sensory hair cells in the vestibular apparatus?
how does the receptor in the semicircular canals work?
endolymph beats against a membrane called a cupula. this is linked to hair cells, whose directional movement directs their neuronal action.
how does the receptor of the otolith organs work?
endolymph moves otoconia (gravel) embedded in a gelatinous membrane. otoconia stimulate the hair cells and kinocillium to direct their neuronal action.
what is the name of the receptor in the semicircular canals?
function of the vestibule and otolith?
linear acceleration perception
hair cells bending towards kinocillium results in?
depolarization and rapid firing
hair cells bending away from kinocillium results in?
hyperpolarization and decreased firing
how does head left rotation affect the neuronal pathway?
vestibular nerve to
vestibulocochlear nerve to
vestibular nucleus to
contralateral abducens nucleus and ipsilateral oculomotor nucleus.
eyes are pulled to look to the right.
what is the name of the tract that connects the vestibular nuclei to the III, IV, and VI nuclei?
medial logitudinal fasciculus
what is the gain of the VOR? what can modify the gain?
gain = 1. cerebellum can modify the gain.
what is nystagmus?
repetitive movement of eyes back and forth. can be jerky or pendular.
what is vertigo?
feeling of motion when stationary
what are some causes of nystagmus?
diseases of retina, labyrinth (meniere's), VIII, cerebellum, brainstem, toxicity
which group of muscles does the vestibulospinal system favour? (think function of vestibulo-)
extensors, to help us maintain balance and stay upright against gravity.
which reflexes help us maintain stable heads during movement?