balance and the vestibular system

the three directions in which the head can rotate

• pitch

• yaw

• roll

pitch

nodding your head up and down

yaw

shaking your head back and forth

roll

moving your head side to side

what do the receptors within the ampulla detect?

head rotation

which structure does the ampulla contain

the cupula, which is deflected by fluid movement

what happens when the cupula deflects?

the stereocilia are displaced, opening mechanically-gated ion channels

which parts of the semicircular canals detect linear motion?

the utricle and saccule, which are at the base of the semicircular canals

what happens when the vestibular ganglion is depolarized?

vestibular hair cells release glutamate onto vestibular ganglion neurons, which are very similar to spiral ganglion neurons.

vestibular-ocular reflex

sensation of movement in one direction causes the eye to move in the opposite direction to stabilize visual images