Vestibular system Flashcards
What are the 3 major functions of the vestibular system
- estimating body position
- postural balance
- control of eye movement
What are the primary functions of the peripheral vestibular system?
to maintain stability in posture during head movement
stabilize images for clear vision
info for spatial orientation
where is the peripheral vestibular system located?
/in the inner ear, next to the cochlea in what is called the vestibular labyrinthine /apparatus
What structures are found within the vestibular labyrinth
bony labyrinth: perilymphatic fluid, supportive connective tissue
membranous labyrinth: Otolith organs, Canals
what are the 2 major components of the Otolith?
Utricle and saccule
what are the 3 canals the feed into the membranous layer of the vestibular apparatus?
anterior canal (A/P) , posterior canal (A/P), lateral canal (longitudinal)
What peripheral nerve carries information from the peripheral vestibular system to central structures?
vestibulocochlear nerve
Where are the otoliths found and what information are these organs sensitive to?
they are found distal to the cochlea and inside the membranous vestibular apparatus. they are sensitive to :linear acceleration/deceleration as well as static head position
the utricle detects movement in what plane?
horizontal
the saccule detects movement in what plane?
vertical
How do the otolith receptors respond to head movement?
via the stereocilia send neural input to the connected nerve fibers. the longest ones, known as the kinocilium, receive info first and determine the direction (inhibitory/excitatory) of the signal to be sent.
What is the function of the macula?
it is the gravity dependent gelatinous membrane encasing the hair cells
What is the function of the otoconia?
these are relatively heavier calcium crystal deposits that enhance the signals received by the kinocilia when in place. When out of place, they can cause vestibular problems like VPPV.
How does the structure of the otoliths allow them to be sensitive to a full
representation of spatial movement and positioning?
They are oriented in all different angles within the saccule and utricle wich in themselves are irregularly shaped and positioned for more reception potential
Where are the semicircular canals and what type of information are they sensitive to?
located in bony labyrinth and filled with endolymph; sensitive to angular velocity
