Vestibular System Flashcards
What are the sensory receptors for the vestibular system?
Hair cells
T/F sound pressure waves activate vestibular hair cells
False
Where are hair cells located?
ampulla of the semicircular canals (3) and the utricle and saccule of the otoliths (2)
What is the blood supply to the inner ear?
the internal auditory artery
(Basilar–> AICA–> internal auditory artery
T/F due to their high energy demand, these structure are highly susceptible to ischemia?
True
What do the hair cells on the utricle and saccule sense?
linear acceleration and gravity
What is the macula?
The sensory epithelium that the hair cells sit in (in the otilith?)
What are otoliths?
crystals of calcium carbonate that sit on top of the gelatinous otolithic membrane to add weight (that can bend the hair cells)
When you tilt your head back, the hair cells move back/forward.
Back
When you acceleration, the hair cells move back/forward.
Back (so opposite)
The utricle cells sit in a _____ plane, and are sensitive to ______ motion
horizontal; forward/backward or side to side acceleration and head tilts where the head is not perfectly straight up and down relative to gravity
What are car hair cells?
The cells in the macula of the utricle
What are elevator hair cells?
Cells in the macula of the saccule
The saccule cells sit in a ___ plane, and are sensitive to _____ movement
Vertical; up and down (and forward and backward)
At the end of each semicircular canal is a ____, and inside that is a tissue ridge of sensory epithelium called a _______ that is embedded in a gelatinous mass called a _______
ampulla; crista; cupula
How do hair cells in the ampullas move?
Fluid moves the cupula which causes activity in the vestibular neuron to increase or decrease
When you turn your head to the right, the fluid in the ampulla moves to the ____
left –> this bends the hair cells in the opposite direction
Where is the vestibular nuclei?
The pons/medulla junction
Vestibular Nerve cell bodies are located in _____
The vestibular (Scarpa’s) ganglion
The Vestibular nuclei projects to the ______ for motor correction
Cerebellum
The vestibular nuclei project to the _____ for spatial orientation
posteriolateral thalamus
The vestibular nuclei project to the ______ for gaze stabilization
extraoccular muscles
The vestibular nuclei project to the _____ for stabilization of head and body posture
Spinal cord via vestibulospinal tracts
T/F Vestibular nuclei have strong connections across the midline?
True
T/F The Vestibular reflexes do NOT work without a cerebellum
False
Much of the vestibular input to the cerebellum goes to _______
flocculonodular lobe
The projections to the thalamus activate which parts of the cerebral cortex?
Insula, somatosensory cortex, and the PARIETAL OPERCULUM
Most of the otolith input acts on the spinal cord via the _______ tract
Lateral vestibulotract
The semicircular canal inputs act via the _______ tract
medial vestibulospinal tract
The otliths ultimately affect ______ to adjust ______
proximal muscles; body position
The semicircular canals ultimately control _____ postion
Head position
The semicircular horizontal canals affect rotation in the _____ plane
Horizontal
What are the 3 major vestibular reflexes?
Vestibulo-ocular
Vestibulo-cervical
Vestibulo-spinal
The left anterior and right posterior (LARP) canal affection rotation where?
The vertical plane skewed 45 degrees anteriorly and to the left
the right anterior and left posterior (RALP) semicircular canal cause rotation where?
In the vertical plane skewed 45 degrees anteriorly and to the right
The horizontal semicircular canals are in the same plane as the _____ and ____ muscles
Lateral and medial rectus
The LARP canals are in the same plane as the ____ and _____ muscles
“vertical” recti (sup and inf) and right obliques
The RALP canals are in the same plane as the ____ and ____ muscles
“vertical” recti and left obliques
What is caloric testing?
a method for evaluating the integrity of the vestibular apparatus of each ear, independently
When you place warm water in someone’s left ear, their eyes will move to the ____
right, but will quickly move back to the left to keep them focused on a target (coWS)
Cold water to the right ear results in ____-beating nystagmus
left (COws)
A patient with an intact vestibulo-ocular reflex (as determined by caloric testing) must have an intact _______ and that _______ is the real issue
brainstem; diffuse cortical depression
