Vestibular System

Question 1

Two organs of the vestibular labyrinth

Answer 1

Semicircular canals- crista

• sensitive to hear rotation
• angular acceleration
• hair cells

Otolithic organs- saccule & utricle

• gravity/ tilt of head
• linear acceleration
• hair cells

Question 2

Differences between cochlear hair cells and vestibular hair cells

Answer 2

1. Kinocillium - adjacent hair cell that runs along the top of the tallest hair cell
2. ## Orientation- vestibular hairs are not all orientated in the same directionAre largely similar however

Question 3

Role of semicircular canal- crista

Answer 3

Head rotation

Question 4

Role of otoliths organs

Answer 4

Gravity/ tilt of head 
Linear acceleration (a lift starting)

Question 5

What is the orientation of the organs of the vestibular labyrinth

Answer 5

Utricle- horizontal

Saccule- vertical

Question 6

How is head movement detected

Answer 6

1. Gravity pulls otoliths either towards or away from kinocillium
2. Differential orientation means some hyperpoalrise some depolarise
3. Change in rate of nerve firing

Question 7

What are the two vestibular nuclei

Answer 7

1. Medial- limb motor neurones and cerebellum

2. Lateral- extraoccular motor neurones and neck motorneurones