Which structure in the ear is involved in converting mechanical vibrations to electrical signals?

The cochlea is the correct answer because it is a fluid-filled structure in the inner ear that plays a key role in the process of hearing. When sound waves enter the ear, they first cause the tympanic membrane (eardrum) to vibrate. These vibrations are then transmitted through three tiny bones in the middle ear (ossicles) to the oval window, which also vibrates.

As the oval window vibrates, it creates waves in the fluid within the cochlea. The cochlea contains hair cells that are sensitive to these fluid movements. When the fluid in the cochlea moves, it causes the hair cells to bend. This bending of the hair cells generates electrical signals through a process known as transduction, which are then sent to the brain via the auditory nerve. This conversion of mechanical vibrations to electrical signals is essential for the perception of sound.

Understanding the role of the cochlea highlights its importance in transforming physical sound waves into a format that the nervous system can interpret, fundamental to the process of hearing. Other structures listed do not participate directly in this conversion; they play different roles in the hearing process.