Vestibular system

Question 1

What is the function of the vestibular system?

Answer 1

Required for balance - is the sensory organ for detecting sensations of equilibrium

Function:

• Providing spatial reference for other sensory motor co-ordinations
• Providing compensatory reflexes (Vestibular Ocular reflex)
• Tuning cardiovascular function for re-orientations
• Helping with perception of motion in space
• Controlling balance reactions

Question 2

What are the three sections of the vestibular system?

Answer 2

Input, Central processing system and the output.

Input - visual, rotation/gravity (controlled by the vestibular organ in the inner ear), pressure (proprioceptors)
Central processing system - mainly brain stem, other parts of the brain.
Output - mainly reflexes: Ocular reflex, postural control

Question 3

What are the organs within the vestibular organ?

Answer 3

5 organs inside - 2 otolith organs (Utricle and saccule) and 3 semicircular canals (lateral, anterior and posterior)
All the semicircular canals are attached to the utricle. The anterior and posterior canals join together before joining to the utricle. The wider side of connection is where the cells for transduction actually are.

The saccule is connected to the utricle and also to the cochlea.

Outside the membranous labyrinth and between the bone there is perilymph but inside the labyrinth there is endolymph. The whole system is in liquid, which transmit vibration
See diagram

Question 4

Describe the innervation of the vestibular organ

Answer 4

Innervates by the vestibulocochlear nerve which has a vestibular part and a cochlear part.

Question 5

What the hair cells involved in transduction?

Answer 5

Type 1: more in number, direct afferents, indirect efferent

Type II: Direct afferents and efferents