Vestibular Physio Flashcards
what does the vestibular apparatus consist of?
utircle
saccule
semicircular canals
what is sensory cell of vestibular apparatus?
hair cells
what are stereocilia/kinocilia surrounded by is vestibular area?
endolypmph so high K+ again
the utricle is in charge of sensing what motion?
linear acceleration in horizontal plane
the saccule is in charge of sensing what motion?
linear acceleration in vertical plane
what is just above the hair cells and surrounds them in vestibular apparatus?
gelatinous layer
what is in the gelatinous layer of the vestibular apparatus?
calcium carbonate crystals
explain the role crystals play in sensing movement in vestibular apparatus
as head moves the crystals are pulled by gravity and move the stereocilia in opposite direction
what is at the base of each semicircular canal?
the ampulla
what does the ampulla have in it?
hair cells with stereocilia
how do semicircular canals sense movement?
fluid in them pushes against the stereocilia in the ampulla as the head moves and that leads to depolarization or hyperpolarization
how many semicricular canals are there?
3…all in different planes
do you need input from one or both sides to understand what is happening in vestibular sense?
BOTH
where does balance info go after the 8th cranial nerve?
to the vestibular nuclear group
what are the two places that vestibular nerve axons can synapse?
vestibular nuclei or the cerebellum through the inferior cerebellar peduncle
axons of the vestibuar nuclei enter the cerbellum via what?
inferior cerebellar peduncle
how do vestibular nuclei help control eye movements?
they project to the MLF
what is linked through the MLF? hint 2 cranial nerves
occulomotor and abducens nerves
the abducens nucleus sends signals to what two spots?
abducens nerve and occulomotor nucleus
how does the abducens nucleus send info to occulomotor nerve?
through the MLF
what two things send signals to the abducens nucleus?
PPRF and vestibular nuclei
what is the PPRF?
parapontine reticular formation
what is the voluntary control of abducen/occulomotor eye horizontal movement?
frontal eye fields….to PPRF
what is the involuntary control of abducen/occulomotor eye horizontal movement?
vestibular nuclei to the PPRF
