Motor control: vestibular system

Question 1

4 functions of vest. system

Answer 1

1. keep eyes fixed on object during head movement
2. keep head balanced during body movement
3. keep upright against gravity
4. conscious perception of gravity

Question 2

2 main players in vest. system

Answer 2

1. otolith organs

2. semicircular canals

Question 3

2 funct of otolith and what detects them

Answer 3

1. linear motion in the plane of gravity (saccule)

2. linear motion in the horizontal plane (utricle)

Question 4

function of semi-canals

Answer 4

detect angular velocity of head

Question 5

what is plane of utricle and saccule

Answer 5

utricle - semi-horizontal

saccule - semi-verticle

Question 6

what fills semi-circular canals

Answer 6

endolymph

Question 7

what are otolith organs and where are they

Answer 7

contain hair cells and crystals and live in the utricle ans saccule

Question 8

what tells saccule about movement

Answer 8

otoconia (crystals) move the over hairs and creates the sense of motion

Question 9

what tells semi canals about movement

Answer 9

cristae ampullaris has cupola overtop that senses the endolymph moving over it

Question 10

3 things vest. and otolith info is used for

Answer 10

1. adjust eye movements during movement
2. generate perception of acceleration
3. correct for changes in body positions

Question 11

what is VIII nerve tonic state when resting

Answer 11

active slow firing

Question 12

what happen when move hairs in preferred direction (towards kinocillium)

Answer 12

faster firing

Question 13

what happen when move hairs in opposite direction

Answer 13

slower firing

Question 14

what happens when move head to left

Answer 14

lymph appear to move right > Left ear fires faster, right ear fires slower

Question 15

what is done with info from left ear

Answer 15

projected to L vest nuc. > tells ipsi 3rd nuc and contra 6 nuc to move eye to right

Question 16

what connects info from vest, occulomotor, troclear, and abducens info

Answer 16

medial long fasiculis

Question 17

what is the VOR

Answer 17

visual ocular reflex (what was just outlined)

Question 18

what can modify the VOR

Answer 18

the cerebellum

Question 19

what does this modification result in?

Answer 19

vertigo and nystagmus

Question 20

what is vertigo

Answer 20

hallucination of movement

Question 21

3 ways to screw the vestibular system

Answer 21

1. injur
2. overstim.
3. continuous rotation

Question 22

what are 2 phases of nystagmus

Answer 22

1. fast - specifies the direction of movement

2. slow - trying to make up movement

Question 23

5 diseases causing nystagmus

Answer 23

1. retinal lack of visual fixation
2. labrinthitits
3. VIII neuropathy
4. cerebellum
5. brainstem

Question 24

4 ways to give healthy people nystagmus

Answer 24

1. spinning
2. temp stim (heat the ear or cool it)
3. optokinetic (subway sign)
4. booze

Question 25

what is vestubulospinal system

Answer 25

descinding motor pathway that contributes with rubro, cortico, reticulospinal pathays

Question 26

3 things vestubulospinal is responsible for

Answer 26

1. control reflex gain
2. select motor program
3. activate groups of motoneuron

Question 27

what muscle groups does vestubulospinal tend towards

Answer 27

extensors (for balance)