What structure in the human ear is primarily responsible for the sense of balance?
1 Answer
Human ear is divided in external, middle and inner parts. Inner ear contains both organs of hearing and balance.
Explanation:
Inner ear is a 'tube within tube' structure: outer one is bony labyrinth and inner one is membranous labyrinth. There is endolymph fluid in membranous tube, and outside it, bony tube is filled with perilymph.
The inner ear is structurally divided in: vestibule, cochlea and three semicircular canals. Vestibule has utricle and saccule. Semicircular canals open in utricle by three dilated ampullae.
There are patches of sensory hair cells in the inner wall of utricle, saccule and ampullae. Sensory hairs of such cells remain embedded in jelly like masses called cupula which lie above every sensory patch and all cupula float in endolymph.
Any change in position of head causes movement of endolymph; this causes displacement of cupula, in turn bending the sensory ends of hair cells. Simulation of nerve endings in sensory patches of utricle, saccule and ampullae thus takes place.
Nerve impulse from here reaches the brain by eighth cranial nerve and we become aware of our body's position.
