Vestibular function

Question 1

What is the vestibular system?

Answer 1

A sensory system essential in the control of posture and balance

Question 2

Vestibular apparatus comprises of…

Answer 2

3 semi circular canals
utricle
saccule

Question 3

What are the swellings at the bottom of the semi circular canals called?

Answer 3

ampulla

Question 4

What do the ampulla contain?

Answer 4

cristae made of cupula containing sensory hair cells

Question 5

What are the otolith organs?

Answer 5

utricle and saccule

Question 6

What do each of the vestibular apparatus detect?

Answer 6

SSC: rotational acceleration

utricle: horizontal - back/front tilt
saccule: vertical acceleration

Question 7

What is cupula?

Answer 7

gelatinous material stretching across ampulla

Question 8

What nerve do the ciliary hair cells synapse with?

Answer 8

CN 8 - vestibulocochlear nerve

Question 9

Why does the endolymph not initially move?

Answer 9

inertia

Question 10

Why does the ampulla move instantly?

Answer 10

embedded into skull

Question 11

What happens if there is sudden stop in movement and the endolymph keeps moving?

Answer 11

dizziness and movement

Question 12

What are the 2 types of cilia of hair cells?

Answer 12

kinocilium - single, large

stereocilia

Question 13

Does distortion away or towards kinocilium result in APs firing?

Answer 13

towards kinocilium

Question 14

Where does integration of sensory information happen?

Answer 14

cerebellum

Question 15

What are maculae and what are the ways they are arranged?

Answer 15

sensory receptors in otolith organs

utricle: horizontal and saccule: vertical

Question 16

What do the cilia protrude into in the otolith organs?

Answer 16

otolith membrane with calcium carbonate crystals (otolith) embedded

Question 17

What is otolith?

Answer 17

CaCO3 crystals

Question 18

Are otoliths or endolymph affected more by gravity and why?

Answer 18

otoliths - denser

Question 19

What do the cerebellar centres co-ordinate?

Answer 19

postural muscles to maintain balance

Question 20

Where do vestibular nuclei receive input from?

Answer 20

proprioceptors - neck, body position etc

Question 21

What is kinaesthesia?

Answer 21

perception of movement and body position

Question 22

What tracts to the vestibular system reflexes involve?

Answer 22

vestibulocortical and vestibulospinal

Question 23

tonic labyrinthine reflexes

Answer 23

keep axis of head in constant relationship with body information

Question 24

Dynamic righting reflexes

Answer 24

rapid postural adjustments - stop falling when you trip

long reflexes, extension of limbs

Question 25

What animal is dynamic righting reflexes most apparent in?

Answer 25

cats

Question 26

Vestibulo-occular reflexes

Answer 26

nystagmus and intortion/extortion | vestibular and visual apparatus and postural control

Question 27

If there is right rotation which side of nystagmus would there be?

Answer 27

right and then change to left after it finishes

Question 28

caloric stimulation: COWS

Answer 28

water - showing horizontal semi circular canals | cold opposite, warm same side - for nystagmus

Question 29

What is nystagmus?

Answer 29

constant uncontrolled movements of the eyes

Question 30

Kinetosis

Answer 30

motion sickness

Question 31

Autonomic nervous system - motion sickness signs

Answer 31

pallor, sweating, decrease BP, nausea, vomiting, dizziness

Question 32

Why does motion sickness happen?

Answer 32

vestibular and visual system inputs to cerebellum in conflict

Question 33

Where do sickness symptoms for motion sickess go to?

Answer 33

hypothalamus

Question 34

Labyrinthitis

Answer 34

infection interfering with vestibular function | ANS symptoms and vertigo

Question 35

Vertigo

Answer 35

perception of movement in absence of movement

Question 36

Meniere's disease - what causes it?

Answer 36

overproduction of endolymph leading to increased pressure

Question 37

tinnitus

Answer 37

subjective noise

Question 38

Does tilting the head forward or backward bend towards the kinocilium and lead to depolarisation?

Answer 38

backwards