Question

The site from where the nerve impulse for hearing originates in mammals is

• A. Ear ossicles
• B. Cochlea
• C. Tympanum
• D. Vestibule

Answer 1

The correct option is B Cochlea

Sound waves enter the external auditory canal and cause the tympanic membrane to vibrate. Back and forth movement of tympanic membrane amplify the sound waves.

Ear ossicles are associated with amplification of sound waves as passing from inner surface of tympanic membrane through through oval window to basilar membrane. Vibrations of basilar membrane stimulate the hair cells (mechanoreceptors) of organ of corti to generate nerve impulse which is then carried to brain via auditory nerve.

Organ of corti is located in cochlear canal/cochlear duct/scala media and has hair cells on its basilar membrane. Vestibular apparatus consists of three semicircular canals, cristae and two sacs called as saccule and utricle.

Vestibule is the organ of sense of balance and is not associated with hearing. Therefore, the correct answer is option B.