The Vestibular System Flashcards
What is the vestibular system?
The system which enables us to balance
It is a somatosensory system which comprises a set of receptors in each inner ear that respond to body position and to movement of the head - localised in our inner ear
What is in each ear?
A vestibular organ which contains three semicircular canals and otolith organs - utricle and saccule
What are the functions of the vestibular organs?
Tells us the position of the body in relation to gravity
Signal changes in the direction and speed of head movements
How is the rotational system encoded?
When the head moves, fluid (endolymph) located in the cells pushes against hair cells, causing bending of the cilia located on top of the hair cells. Responds to angular acceleration. Bending of cilia leads to receptor potentials in the hair cells and action potentials in the cells, the direction the cilia are bent determines whether the hair cell becomes depolarised or hyperpolarised
What happens when your head tilts?
The utricle and saccule contain hair cells which are embedded in a gelatin like substance which contains crystals of calcium called otonconia. Responds to linear acceleration. When the head is tilted, the gelatine and otoconia push against the hair cells, which alters the rate of action potentials in the cell that forms the vestibular nerve
