Which part of the inner ear converts sound into electrical signals?

The cochlea is the crucial structure in the inner ear that converts sound into electrical signals. It is a spiral-shaped organ filled with fluid, and it contains a specialized structure known as the organ of Corti, which is lined with hair cells. When sound waves enter the cochlea, they create pressure waves in the fluid, causing the hair cells to vibrate. This mechanical movement of the hair cells leads to the generation of electrical impulses, which are then transmitted to the auditory nerve and ultimately to the brain, where they are interpreted as sound.

In contrast, the semicircular canals are involved in maintaining balance and spatial orientation, rather than converting sound. The vestibule plays a role in balance as well, specifically concerning linear movements and gravitational forces. Lastly, the auditory canal is a passageway that channels sound waves to the eardrum but does not have a role in converting sound into electrical signals. Thus, the cochlea is distinctly responsible for the essential process of transforming sound vibrations into the electrical activity that the brain can understand as sound.