How Humans Hear

Sound entering the ear canal causes the eardrum to vibrate. These vibrations are picked up by three tiny bones in the middle ear that connect the drum to the cochlea, a snail-shell-like structure with three tubes filled with fluid. The resulting waves in the fluid signal hair cells in the cochlea that transmit electrical signals to the auditory nerve that connects to the brain stem. These signals then travel to the brain’s auditory center, where the message is processed.