Which structure in the ear is responsible for hearing?

The cochlea is the structure in the ear that is primarily responsible for hearing. It is a spiral-shaped, fluid-filled organ located in the inner ear. When sound waves enter the ear, they cause the eardrum to vibrate, which then transfers these vibrations to the ossicles (tiny bones in the middle ear) and subsequently to the oval window, a membrane that leads to the cochlea.

Inside the cochlea, the vibrations create waves in the fluid, which in turn stimulate hair cells along the basilar membrane. These hair cells convert the mechanical vibrations into electrical impulses that are sent to the auditory nerve and ultimately to the brain, where they are interpreted as sound. This intricate process makes the cochlea crucial for the perception of pitch and volume.

Other structures in the ear, such as the auditory canal, vestibule, and semicircular canals, play important roles in balance and the overall architecture of the auditory system but are not directly involved in the process of hearing.