Vestibular Flashcards
(16 cards)
What do the otolith organs respond to?
-Linear acceleration
-Head tilt
What do the semi-circular canals respond to?
Rotational acceleration
What’s the ionic environment in the endolymph?
K+ > Na+
What’s the ionic environment in the perilymph?
K+ < Na+
What’s the endocochlear potential?
There’s an 80mV difference between the scala media and scala tympani
What does “otolith” mean?
“ear stones”
True or False? Tilting the head on one side has opposite effects on corresponding hair cells on the other side
True, it’s a mirrored system
If there’s only 3 semi-canals and each have single directional hair cells, how do they consider all possible rotation axis?
Work in pairs, one per ear, with opposing directionality
What reflexes involve the vestibular system?
equilibrium & gaze
posture & balance
What higher order processes involve vestibular system?
spatial orientation (am I moving?)
self-motion (is the world moving?)
True or False? The vestibular system sends information to the primary vestibular cortex
False. There is no cortex, it’s highly integrative and takes information from many places
What’s nystagmus?
Slow eye movement in the opposing direction of head turn due to difference in firing rate of ear canals
What’s a clinical application of nystagmus?
Comatose patients can be injected with cold and warm water
Only slow movement, intact brainstem
What’s oscillopsia?
bouncing vision, can’t fixate while head is moving
unilateral can be compensated
bilateral makes you think the world is moving if you move your head
What happens if the brainstem is severed above the vestibular nuclei?
Decerebrate rigidity (anti-gravity always on)
What’s one way to solve decerebrate rigidity?
Lesioning the vestibular nuclei
