Vestibular function Flashcards
What are the two otolith organs?
Utricle and Saccule.
What are the otolith organs sensitive to?
Linear acceleration and position of the head with respect to gravity.
What is the name of the vestibular organ found within the utricle and sacule?
Macula.
When the head is upright, the macula of the utricle is oriented…..
Parallel to the ground.
When the head is upright, the macula of the saccule is….
Verticle to the ground.
If the head is bent forward 30 degrees the horizontal cells….
Become parallel to the ground.
Why do patients experience post-rotatory nystagmus?
This is vestibular nystagmus occuring after a person stops turning due to the endolymph having interia.
Post-rotatory nystagmus will point in which direction?
Will always point in the direction opposite the spinning.
Thus this is an illusionary turning that the mind responds to.
Describe the direction of slow phase nystagmus.
Always turns in the direction opposite of head turn to try and maintain fixed gaze.
Describe the direction of the fast phase nystagmus?
Moves the eyes back to the midline in the direction of the turn.
Will not occur in comatose patients
What is BPPV?
This is a benign type of vertigo caused by free floating particles in the posterior semicircular canal.
Can be seen in the eyes.
There is no decreased hearing.
What are the causes of Meniere syndrome?
Problem with production and reabsorption of endolymph leading to rupture of the mebranous labyrinth.
Vertigo, nausea, vomiting and abnormal eye movements are seen.
Presents with feeling of ear fullness and pressure with decreased hearing.
How many vestibular nuclei are present?
There are 4 pairs in the rostral medulla and caudal pons.
What are the primary inputs to the vestibular nuclei?
Primary vestibular afferents and neck proprioceptors.
What are the outputs of the vestibular nuclei?
Thalamus to cerebral cortex
Provides conscious awareness of body orientation and motion.
