FE: Lecture 4: Vestibular Part 2 Flashcards Preview

Neuroscience Final Exam > FE: Lecture 4: Vestibular Part 2 > Flashcards

Flashcards in FE: Lecture 4: Vestibular Part 2 Deck (15):

Where are the vestibular hair cells located?

in the utricle macula, saccule macula and ampullary crests


How does hair move in the organs?

depolarized by force in direction of the arrows, however in the ampulla the hairs are unidirectional


What is the path of the AP from hair to end?

1. synapse from hair to primary afferent fibers

2. fibers go to scarpa's ganglia then synapse in ipsilateral vestibular nuclei

3. ampullary crest goes to medial and superior nuclei- detects head rotation (angular acceleration)

4. maccula of utricle and saccule go to lateral nucleus (tilt and linear acceleration)


Where are the vestibular nuclei?

1. inferior and medial nuclei in the medulla

2. medial, superior and lateral are in the pons


What is another name for the vestibular hair cells?

crista ampullaris- hair cells have same orientation


What is function of the cupulla in the ampulla?

this amplifies the force of the flow of endolymph


How is the movement of endolymph initiated?

any time you rotate your head the endolymph will move, this will either bend the stereocilia towards or away from the kinocilia


In regards to hyper and depolarization what rotations are needed for each?

ipsilateral rotation- depolarizes

contralateral- hyperpolarizes


If your turn your head to the left what happens in the ampulla?

left ampulla turns left and endolymph goes to the right which depolarizes the left side


What happens for in order for the Vestibular- Ocular reflex (VOR) or Doll's eye reflex?

after synapsing at the vestibular nuclei the AP travels of the MLF this excites the contralateral abducens nerve and ipsilateral Oculomotor nucleus which then sends LMN to those muscles


Therefore what happens when your turn your head to the right?

right vestibular nuclei activated due to flow of endolymph flowing toward kinocilia

this activates Left eye ABD, Right eye ADD


How many degrees does a normal VOR usually work?

15 degrees then eyes jump back to center


What is movements behind nystagmus?

slow then fast eye movements

slow drift opposite of head rotation then jump back in same rotation


What is the functional anatomy behind nystagmus?

slow phase- vestibular nuclei

quick phase- pontine reticular nuclei


What is abnormal nystagmus?

head is fixed but constant nystagmus

due to vestibular lesion