Ear

The ear is the organ through which humans and most animals hear sound. It converts sound waves traveling through air into neural signals that are sent to the brain. The human ear also participates in the body's balance system and the sense of spatial orientation of the head.

The ear is conventionally divided into three parts: the outer ear, the middle ear, and the inner ear. Each part has a specific function in capturing, amplifying, and converting sound.

Outer ear

The outer ear consists of the visible part located on the side of the head and a canal extending inward. The visible part helps collect sound waves and identify the direction from which they come. The canal ends in a thin membrane that vibrates in response to sound.

Middle ear

The middle ear is located in a small air-filled cavity. Within it are three tiny bones connected to each other that transmit vibrations from the eardrum to the inner ear while amplifying them. A tube connecting the middle ear to the throat and mouth regulates air pressure; this is why the ears respond to changes when flying or climbing a mountain.

Inner ear

The inner ear contains a spiral-shaped structure filled with fluid, which has tiny hair cells that convert vibrations into neural signals. It also contains circular canals connected to the senses of balance and head movement. These signals are transmitted to the brain by the hearing nerve.

Health and disease

Hearing loss can result from many causes: fluid accumulation in the middle ear, wax buildup in the canal, age-related deterioration, or prolonged exposure to very loud sounds. Some of these conditions are treatable, while others require hearing aids. Hearing screening in young children is important for language development.