Question

Ear dust is not situated in endolymph of

• A. Utriculus
• B. Ampulla
• C. Sacculus
• D. Endolymphatic sac

Answer 1

Answer: (B)

Ampulla

While semicircular canals respond to angular acceleration in specific directions, hair cells in the utricle and saccule respond to linear accelerations. The utricle and saccule are sac-like structures, that contain a patch of sensory hair cells called as the macula. The hair cells in the macula, which are similar to those in the cristae, are embedded in the otolith (ear stone) membrane, a gelatinous structure, that contains a large number of hexagonal prisms of calcium carbonate called as otoconia (ear dust).

Since the density of the otoconia is greater than the surrounding endolymph, the otolith membrane will be displaced by the force of gravity or other linear accelerations. In humans, the enlarged ends of each of three semicircular bony canals in the inner ear are known as osseous ampullae. Tiny hairs in this ampullae help to keep the brain informed of how the head is oriented, helping the person's sense of balance.

Therefore, the correct answer is option B.