vestibular system Flashcards
what are responsible for angular motions?
semicircular canals
what is responsible for linear motion?
vestibule
what is perilymph?
CSF and is high and Na
this is outside of membrane
sits between the bone and the membrane
what is endolymph?
fluid that is high in K
this is inside of membranes
what are the three semicircular canals?
superior
posterior
horizontal
what motion would the superior semicircular canal detect?
a nod for yes (up and down)
what motion would the posterior semicircular canal detect?
head tilt left or right (ear towards shoulder)
what motion would the horizontal semicircular canal detect?
shaking head no ( left and right axial rotation)
how do the semicircular canals overcome inertia?
the cupula is a sack that covers the hair cells. The sack is full of endolymph
what are the organs that make up the vestibular system?
utricle and saccule
(otolithic organs)
these sense linear motion
gravity
what are otoconia?
calcium crystals, these move with gravity. as you go up the move up and as you go down they hit the hair cells.
what is the striola?
the bag that holds the otoconia
what is the otolith membrane?
the sack to covers the hair cells and is what moves the hair cells depending on the movement
what does multimodal convergence mean?
immediate integration with other sensory inputs
where is the central vestibular nucleus located?
pons/medulla
dorsal portions
what are the four major central vestibular nuclei?
superior(all in the pons) lateral, medial, and inferior vestibular nuclei
with cilium how are the potassium channels open?
stretch activated
depending on the direction of bend, it will either activate or slow down the signal
in the utricle and saccule how are the hair cells aligned?
in opposite directions
where are the hair cells located in the semicircular canals?
in the ampulla of each canal
what does the horizontal canal do?
adjusts your eyes based on head movement via the superior vestibular nucleus
Vestibulo-cerebellar network
superior vestibular nucleus
-impulse directly from the semi circular canals that goes to the cerebellum.
-coordination of:
posture
balance
eye movements (saccade control) fast movements of the eyes.
Vestibulo-ocular network
- horizontal canal to the superior vestibular nucleus.
- horizontal eye movement.
- *control is in the pons**
what is nystagmus?
eyes drift/jerk to the opposite side of head movement first(slow) and then quickly jerk to the side of motion.
pathway from the horizontal canal to the muscles?
vestibular nucleus (superior, pons) to the abducens nucleus (pons) and then to the contralateral lateral rectus and oculomotor (along the medial longitudinal fasiculus)