Final answer:
Sound waves in the cochlea cause the hair cells to generate an electrical signal that is sent to the brain.
Step-by-step explanation:
When sound waves enter the cochlea, they cause the tectorial membrane to vibrate, which in turn stimulates hair cells. The hair cells have cilia that respond to the movement of the tectorial membrane by bending. This bending of the cilia results in the opening of gated ion channels, leading to depolarization of the hair cell membrane and the generation of an electrical signal. This signal is then transmitted by the cochlear nerve to the brain, where it is further processed.