ch 3b- sensory contribution continued

Question 1

Vestibular system

Answer 1

detects head motion/acceleration and body movements

Question 2

components of vestibular system

Answer 2

-Otoliths: saccule and utricle
-Semicircular canal: posterior, superior and horizontal

Question 3

Otoliths

Answer 3

sense linear head acceleration
-saccule detect acceleration in vertical plane
-utricle detects acceleration in horizontal plane

Question 4

Semicircular canals

Answer 4

sense angular head acceleration
(rotation or tilting)

Question 5

saccule

Answer 5

vertical linear acceleration

Question 6

utricle

Answer 6

horizontal acceleration

Question 7

how to semicircular canals detect movement?

Answer 7

canals are filled w endolymph (rich in K+), endolymph displaces cupula when head moves. cupula has hair cells embedded
–> depolarization because influx on K+, action potential

Question 8

How do otoliths detect movement?

Answer 8

otolithic membrane contains otoconia stones. lags behind head motion, deflects hair cells
–> action potential

Question 9

functions of the vestibular system

Answer 9

1. gaze stabilization (via vestibular ocular reflex; head moves then eyes move)
2. postural stabilization= maintain balance via vestibulospinal reflexes

Question 10

GVS (galvanic vestibular stimulation)

Answer 10

current on bones behind ears. activates vestibular afferents and hair cells causing illusion of head tilt and results in compensatory tilt in opposite direction

Question 11

cathode (-) on right side

Answer 11

perceive head tilt right

Question 12

anode (+) on right side

Answer 12

perceive head tilt left

Question 13

visual field

Answer 13

region of space where the eye sees. shifts w eye movements

Question 14

central vision

Answer 14

identifying details. mostly cones

Question 15

peripheral vision

Answer 15

where things are. envmt context and limb movement. mostly rods