vestibular system

Question 1

function of the vestibular apparatus

Answer 1

maintain upright posture, adjust head position in response to changes in posture, coordinate eye movements with each other, coordinate eye movements to compensate for head movements

Question 2

linear vs angular acceleration

Answer 2

linear acceleration: head moving along a single plane

angular acceleration: head rotation in single plane or simultaneous change in velocity/direction

Question 3

maculae

Answer 3

in the utricle and saccule detect linear acceleration,
projecting from the surface of hair cells are stereocilia arranged in rows that abut a kinocilium

the macula in the utricle lies in the horizontal plane
the macula in the saccule lies in the vertical plane

cilia are polarized toward a ridge

stereocilia deflection towards the kinocilium leads to hair cell depolarization
the pattern of hair cell signalling across the maculae is transmitted via CN VIII

Question 4

semicircular canal

Answer 4

have enlarged ends called ampullae

each ampulla contains a ridge of sensory epithelium (crista ampullaris)

crista ampullaris is the location of sensory epithelium thats covered by gel material (cupola)

Question 5

semicircular canals

Answer 5

detect changes in the spead of head rotation

horizontals are paired
the r superior and l post
l sup and R post

Question 6

central vestibular path

Answer 6

prevent tripping
4 vestibular nuclei
Caudal pons: sup and lateral vestibular nuclei
Rostral medulla: medial and inferiorr

Question 7

lateral vestibulospinal tract (LVST)

Answer 7

maintains balance and posture

Question 8

medial vestibulospinal tract

Answer 8

adjusts head postion in response to postural changes

coordinates eye movements with eachother

reflexively coordinates eye movements to compensate for head movements (vestibuloocular reflex)

vestibular nuclei send sensory input regarding head movement to contralateral abducens nucleus

each abducens nucleus is in communication (via MLF) with the contralateral oculomotor nucleus

the eyes are yoked together resulting in a conjugate horizontal gaze

Question 9

central pathway for the VOR

Answer 9

neuron 1: sensoryy neurons with cell bodies in vestibular ganglion detect head movement and send signal to vestibular nuclei

neuron 2: neurons in vestibular nuclei project to brainstem nuclei that control extraocular muscles

neuron 3: