14 Vestibular System Flashcards
inner ear consists of two main sections which are
inner membranous labyrinth
outer bony labyrinth
bony labyrinth consists of three areas:
semicircular canals
vestibule
cochlea
These contain the receptors for equilibrium
semicircular canals and the vestibule
This system maintains stable eye and body position in response to changes in head positioning.
vestibular system
Within the vestibule are the parts of the membranous labyrinth which are
utricle
saccule
-is the sensory receptor area of the utricle and saccule
-has receptor hair cells that are embedded in an otolithic membrane consisting of a gelatinous material covered by a glycoprotein studded with calcium carbonate crystals called otoliths (otoconia), which are relatively heavy
macula
The utricle receptors lie in a ____ plane, and those of the saccule lie in a ____ plane
horizontal
vertical
what are the three semicircular canals
anterior
lateral
posterior
what is the swollen area at the end of each canal
ampulla
Inside the semicircular canals are the parts of the membranous labyrinth called
semicircular ducts.
Each of the three ampullae in the semicircular canal contains
sensory receptors called the
crista
Sensory receptor cells in cristae ampullaris are hair-like structures called ____ comprising a kinocilium and numerous stereocilia.
sensory hair cells
Each stereocilium is connected to its neighbor called a
tip link
Arising from the crista and completely encapsulating the stereocilia is a gelatinous structure called the
cupula
two types of equilibrium:
static and dynamic
refers to the maintenance of the position of the body while not moving
Static equilibrium
is the maintenance of body position in response to sudden movements such as acceleration, deceleration, and rotation
dynamic equilibrium
structures that are mostly involved in static equilibrium but are also involved in dynamic equilibrium by responding to linear acceleration.
Macula within the utricle and saccule
Movements of the stereocilia toward the kinocilium cause the sensory hair cell membrane to ____ while movements away from the kinocilium cause ____
depolarize
hyperpolarization
The 1st order vestibular afferents arise in
Scarpa’s ganglion or vestibular ganglion
what are the four 2nd-order vestibular nuclei:
inferior vestibular nuclei
medial vestibular nuclei
lateral (Deiter’s) vestibular nuclei
superior vestibular nuclei
The main descending tracts
lateral vestibulospinal tract (from the lateral vestibular nucleus)
medial vestibulospinal tract (from the medial vestibular nucleus)
main ascending tracts?
superior and medial vestibular nuclei to the extraocular muscles through the medial longitudinal fasciculus (MLF)
