Which structure within the inner ear is primarily responsible for hearing?

• A. Cochlea
• B. Olfaction
• C. Light pressure
• D. Discriminative touch

Answer: (A)

Hearing relies on the cochlea in the inner ear, where mechanical vibrations are transformed into neural signals. When sound enters the ear, it sets the eardrum and then the tiny bones in the middle ear into motion, transmitting the vibrations into fluid inside the cochlea. This moving fluid bends the hair cells on the organ of Corti, and their movement opens ion channels to create electrical signals that travel along the auditory nerve to the brain. The cochlea’s structure also helps distinguish different frequencies, contributing to pitch perception.

The other options don’t relate to hearing: olfaction is the sense of smell, processed in the nasal cavity and brain; light pressure and discriminative touch are tactile senses handled by skin and somatosensory pathways, not by the inner ear.