Vestibular System Flashcards
What is dynamic labyrinth
Consists of three pairs of semicircular canals and provides reflex control of eye movements- when the head turns one direction, the eyes turn in the opposite direction- angular acceleration. Sense turning of the head. 1-10Hz
Name three balance related structures of the inner ear
Otolith (utriculus, saccules, macula)
Semicircle canals (duct, ampulla, crista ampullaris)
What is static labyrinth
Is the otolith organ sensitive to 0-1 Hz. Responsive to linear acceleration- like an elevator. When the head tilts the otoliths respond and deflect hairs of hair cells- can measure the direction and amplitude of gravity vector.
What is an otolith
The otoliths are imbedded in the macula. This organ serves a a plumb bob like reference for the head. Responsible for head tilting senses. They are sensitive to gravity and linear acceleration.
What is the macula?
The macula is the neuroepithelium of the otolith organ. receives the utricular filaments of the vestibulocochlear nerve.
Macula and otolith are sensitive to what?
Linear acceleration and gravity.
What is the crista ampullaris?
The crista ampullaris is the sensory organ of rotation located in the semicircular canal of the inner ear. The function of the crista ampullaris is to sense angular acceleration and deceleration.
What is the cupula
The cupula is a structure in the vestibular system, providing the sense of spatial orientation. The cupula is located within the ampullae of each of the three semicircular canals. Part of the crista ampullaris, the cupula deflects,when the head turns.
What are the cupula and crista ampullaris sensitive to?
Angular acceleration- turning movements of the head
What CN supplies the vestibular portion to the inner ear?
CN VIII
Where does CN VIII terminate
The auditory component - cochlear nucleus which is located at the junction of the pons and medulla.
The vestibular part of the eight nerve ends in the vestibular nuclear complex located in the floor of the fourth ventricle.
Brain structure in which primary afferents of semicircular canals and otolith organ terminate.
Medial longitudinal fasciculus
Which region of brain structure do eye movement controlling fibers terminate
Cerebellum
Name the myelinated pathway that links the vestibular nuclei w the eye movement control nuclei
Medial longitudinal fasciculus
What is dolls eye maneuver.
Demonstrates the integrity of the vestibulo-ocular reflex and the medial longitudinal fasciculus. If the head is turned passively to one side, the eyes respond by turning to the opposite side.
