Flashcards in Vestibular Anatomy Deck (53)
Which direction do eyes move with angular movement?
Pitch is sensed by what?
Yaw is sensed by what?
Sensory organ of linear or translation VOR
Otoliths:Saccule and Utricle
Which direction do eyes move with linear movement?
What does the saccule detect?
Linear movement up and down (riding in elevator)
What does the utricle detect?
Linear movement horizontally (riding on a train on a straight track
Sensory organ of ocular tilt reflex:
What direction do eyes and head move in ocular tilt reflex?
opposite tilt of head
What does head tilt to the left cause?
elevation of the left eye, depression of the right eye, torsion of both eyes to the right and the tilt of the head on the body to the right.
What facial nerves does ocular motor nuclei travel for mediation of VOR?
What are the target for vestibular input?
Vestibular Nuclear Complex
What does the cerebellum do?
back-up system for adaption of gain of VOR
Monitors vestibular performance and readjusts central vestibular processing if necessary
VOR (Vestibular Ocular Reflex):
generates eye movements, which enables clear vision while head is in motion
VSR (Vestibular Spinal Reflex):
generates compensatory body movement in order to maintain head and postural stability, thereby preventing falls
VCR (Vestibular Collic Reflex):
stabilizes the head in space
Function of vestibular system:
stabilizes vision when head moves (VOR)
balance control (VSR)
What does visual acuity depend on:
position of image on fovea
ability to hold image steady
Position of image: gaze shifting
for best vision, object within 0.5 of center of fovea
fovea must be moved to achieved proper poistion for vision
saccades, pursuits, vergence eye movement
Holding image steady, gaze holding
optokinetic, visual fixation, vergence and vestibular eye movements
Components of balance control:
gaze stabilization system
postural stabilization system
Gaze Stabilization System
maintains gaze direction of the eyes and visual acuity during activities involving active head and body movements