Balance

Question 1

equilibrium

Answer 1

1) sense of body orientation and motion

Question 2

vestibular apparatus

Answer 2

1) provides information for equilibrium and for coordinating head movements with eye and posture
2) structures
- semicircular canals
- utricle
- saccule

Question 3

circular motion

Answer 3

1) semicircular canals
- rotational or angular acceleration or deceleration of the head
2) three loops arranged in XYZ planes

Question 4

linear motion

Answer 4

1) utricle and saccule

Question 5

crista ampullaris

Answer 5

1) functional sensory unit of rotational motion
- house hair cells (kinocillium and stereocilia)
2) the hairs protrude into the endolymph
3) the hairs are embedded in cupula (gelatinous layer)
4) moving endolymph pushes against he cupula => cupula bow => hairs bend

Question 6

cupula

Answer 6

1) cupula moves against the fluid, causing hair cells to bend
2) when stopped, the fluid continues to move due to inertia
- causes hair cells to bend agains

Question 7

generating receptor potentials

Answer 7

1) endolymph moves => stereocilia deflects => tension on tip links => pull on mechanically gated ion channels

2) channels either open or close (hyper or depolarization)

Question 8

otolith organs

Answer 8

1) utricle and saccule
- linear motion
- functional unit is macula
2) between the semicircular canals and cochlea
3) kinocilium and stereocilia of the receptor hair cells protrude into otolith membrane (gelatinous membrane)
4) otoliths
- calcium carbonate suspended in the gelatinous later
- makes otolith membrane heavier => more inertia

Question 9

utricle and saccule detect

Answer 9

1) by displacement of hairs
2) utricle hairs displaced by changes in horizontal motion
3) saccular hairs displaced by changes in vertical motion

Question 10

forward movement

Answer 10

1) otolith membrane (greater inertia) lags behind => hair cells bend to the rear
2) no acceleration but still moving
- the gelatinous layer moves at the same rate as the hair cells=> hairs no longer bend
3) sudden deceleration => otolith sheet continuous to move forward => hairs bend forward

Question 11

input

Answer 11

1) information about the body’s position in space comes from three main sources and is fed into two major processing areas in the CNS

Question 12

output

Answer 12

1) responses by the CNS provide fast reflexive control of the muscles serving the eyes, neck, limbs, and trunk