Question

Cochlea of mammalian internal ear is concerned with

• A. Balance of body posture
• B. Both balance and hearing
• C. Hearing
• D. Perception of atmospheric pressure

Answer 1

Answer: (C)

Hearing

The inner ear consists of two systems of canals which are namely cochlea and vestibular apparatus. Vestibular apparatus consists of three semicircular canals, cristae and two sacs called as saccule and utricle. It houses the system for equilibrium and serves as a source of essential inputs for maintenance of posture and balance. Mechanoreceptors in semicircular canal detect the rotational movement of the head (rotational equilibrium) while those of utricle and saccule detect the horizontal or vertical movement of the head (gravitational equilibrium). Thus, the disturbance in posture and balance of the body is felt by mechanoreceptors present in vestibular apparatus of the inner ear as well as by proprioceptors. The cochlea is the spiral hollow structure containing three fluid-filled canals. Organ of Corti is located in middle cochlear canal and has hair cells (mechanoreceptors) on its basilar membrane. Thus, cochlea houses sensory system for hearing only and is not associated with balancing. Eustachian tube of middle ear serves as pressure valve by allowing the air into or out of the middle ear to equalize the internal and external pressure on the eardrum. Thus, the correct answer is option C.