Vestibular System- Linda D'sylva Flashcards
What are the three systems that contribute to imbalance and dizziness?
Vestibular, vision, somatosensory
within the vestibular anatomy, what does the peripheral sensory system do?
provides sensory input for both angular and linear acceleration, orients head position in space
within vestibular antomy, what does the central processing system do?
sensory and visual cues
are processed by the brain and relays balance and proprioceptive information
where in the brain is sensory input from the vestibular system processed
cerebellum and reticular formation of the cortex
what does the motor output system of the vestibular system do?
generates compensatory eye movements for gaze stability, this indirectly controls body movements for postural stability with locomotion
what are the semicircular canals sensitive to?
angular change: yaw, pitch, and roll
the horizontal canal sits at ______ degrees
30
the hair cells and crista ampullaris are contained where?
in the ampulla
what is a hair cell’s job?
to convert head motion into neural firings
what three organs house hair cells
ampulla, utricle and saccule
what are the otolith organs?
utricle and saccule
the utricle is oriented in what plane?
horizontal
the saccule is oriented in which plane?
vertical plane
when an elevator starts moving, which otolith organ tells u ur moving upwards in space?
the saccule
when the boat your riding in suddenly stops and throws your uncle and his camera forward onto his face, which otolith organ should’ve warned him he was coming to a stop?
the utricle
the central processing system is comprised of…
cerebellum and vestibular nuclei
when u turn your head, what happens to the firing rates of the vestibular nuclei on either side of your head?
the ones on the side that you turned towards start firing faster (more spikes) and the ones on the side you turned away from slow down (fewer spikes)
what causes dizziness when someone has damage to their vestibular nuclei on one side?
the one vest. nuclei is still firiing but the other one has slowed way down because it’s damaged so the vest. system is saying you’ve turned your head away from that slow side but the visual system says , uh no u didn’t, so there is dizziness.
what are the otolith organs (utricle and saccule) sensitive to?
linear acceleration/ deceleration
the superior branch of CN VIII stimulates which semicircular canals and otolith?
lateral semicircular canal and the utricle
the inferior branch of CN VIII stimulates what?
posterior semicircular canal and saccule
The superior/anterior canal detects change in what direction?
rotations of the head of the anterior/posterior axis, tipping your head forward activates your superior/anterior canal
the lateral/horizontal semicircular canal detects change in what direction?
when head rotates in a transverse plane (turning head L and R before crossing the street. when u turn R u activate the R and inhibit the L
the posterior/inferior semicircular canal detects change in what direction?
when u tip your head back u activate the post./inf canal