Final -Ch. 22 - Vestibular System Flashcards
Job of vestibular system?
Fxns to keep us visually and physically steady in world.
Gaze stabilization is what reflex?
VOR
What is the vestibulospinal tract?
LMN - keeps us upright against gravity
low level of control
located to BS
Which is the conscious relay pathway?
cerebrocortex
Where do the autonomic function and conciousnous have connection to and what do problems in homeostasis indicate?
reticular formation
homeostasis
What are the two parts of Cranial N VIII and what do each do?
cochlea - hearing
vestibular - balance
Describe the location and motion detected by 3 semi-circle canals.
anterior - 45 degrees off centered -
posterior - 45 degrees off-centered -
horizontal - lateral, a bit tilted -
What is located at end of canals and what does it contain?
ampula
hair follicles
What reflex occurs when head is moving but object is not?
optokinetic reflex
smooth pursuits
What is a nystagmus?
fast reset for eyes to detect new object
Where does the pathway from cranial N VIII end?
pons and medulla jx
What are the 5 systems the vestibular Nuclei recipe information from?
vestibular vision proprioception tactile auditory information
Where does the vestibular nuclei send information so equilibrium is conscious and confirmed?
cerebral cortex
Which two cortexes are reciprocally inhibitory?
vestibular and visual
What is Pusher’s syndrome?
PATHWAYS FROM INNER EAR TO CORTEX GET DAMAGED – PT FEELS LIKE THAY ARE FALLING OVER AND WHEN THEY TRY TO PUSH THEMSELVES BACK TO ALIGHNMENT THEY ARE ACTUALLY PUSHING SELF OVER
What are the two vestibular systems we are focusing on?
peripheral - semi-circles and otoliths
Cranial N
What are the two vestibular systems we are focusing on?
peripheral - semi-circles and otoliths
Cranial N
feeling of movement without it (spinning)
vertigo
What are the S&S of vestibular dysfx?
nausea and vomiting
dyesequillibrium - impaired gaze stabilization
VOR is not working, could work in one and not the other
blurry
Oscillopsia
completes lack of gaze stabilization
complete lack of VOR
Unilateral hyperfunction
unilateral / peripheral
one side too excited
one side is more active than it should be
BPPV
sends signals of moving even when I am still
dizziness and nausea esp. vertigo postural instability but stays put reduced gaze stabilization - pathologic VOR temporarily broken
Unilateral Hypofunction
unilateral / peripheral
vestibular neuritis - squeezing Cranial N VIII
one side, night-night
just standing still - fewer signals
sneaks up
BLURRINESS
FEELING LIKE FALLING
gaze instability - absent VOR (eyes move with head)
postural instability - impaired VOR and reduced vestibulospinal (lateral vestibulospinal) activity
vertigo? no
nausea? no
What is oscillopsia? What can cause bilateral oscillopsia?
no gaze stabilization
Cranial N VII both sides
NO VOR at all
medications - ototoxic
