Question

Comment upon the role of ear in maintaining the balance of the body and posture.

Answer 1

Organ of equilibrium :

Vestibular apparatus, in the inner ear, is the receptor organ for equilibrium. It includes the saccule, utricle and membranous semicircular ducts.

Role in maintaining the balance of the body and posture:

The body is said to have two kinds of equilibrium. They are the following:-

• Static equilibrium: Equilibrium of the body with respect to position of head in space is called static equilibrium. This is maintained by the utricle and saccule.

The walls of both the utricle and saccule (also called otoliths organs) contain a small, thickened region of sensory cells called a macula. The maculae also detects linear acceleration for example, the sensations one feels while in an elevator or car that is speeding up or slowing down.

• Dynamic equilibrium: Equilibrium of the body with respect to rotational movement is called dynamic equilibrium.

The ampullae of the semicircular canals contain a projecting ridge of cristae ampullaris that contain sensory cells. The sensory hairs of these receptor cells detects rotational movement converting the movement to electrical impulses. These impulses are carried by the vestibular nerve and finally through the auditory nerve to the brain.