How Do We Hear?

The human ear functions to provide sound, speech, and balance information to the brain. There are three main components of the human ear. The external ear includes the pinna (or outer ear), ear canal, and eardrum. The middle ear includes the three hearing bones, or ossicles. From the eardrum to the inner ear, the three ossicles are the hammer, anvil, and stirrup – the malleus, incus, and stapees. The inner earincludes the cochlea, the organs of balance, the hearing nerve (auditory nerve), and the balance nerves (vestibular nerve).

Sound is captured by the pinna, funneled into the ear canal and vibrates the eardrum. The malleus, connected to the eardrum, vibrates, and transmits this energy to the incus and stapes. The stapes is connected to the inner ear, or cochlea, and vibrates the fluid in the cochlea. A fluid wave, or traveling wave, is created in the cochlea, and causes the hair, or stereocilia, of the inner ear hair cells to bend. This excites the hair cells, and results in an electrical signal being produced, and sent to the auditory nerve. This electrical signal is sent to the brain for processing.