The human ear consists of three parts: the outer ear, the middle ear and the inner ear. The outer ear acts like a funnel to receive and direct sound waves. Sound is conducted through the structure called the ear canal. Stretched across the canal in the middle ear is a membrane called the eardrum. Sound waves cause the eardrum to vibrate. Attached to the eardrum are three small bones. Vibrations pass from the eardrum to these three bones. The middle ear is connected to the throat by a tube called the Eustachian tube. This tube helps to maintain proper air pressure in the ear. In the inner ear is a chamber called the cochlea. The cochlea is shaped like a snail. Inside the cochlea are fluid and tiny hairs. The vibrations from the three bones are passed to the fluid in the cochlea. The tiny hairs are nerve endings that pick up the vibrations from the fluid. The nerve endings send impulses to the brain along the auditory nerve. The brain then interprets the impulses as sounds.

In addition to transferring sound vibrations, the inner ear is important to maintain balance. Balance helps us to adjust to changes in position, direction and gravity. Within the inner ear are three semicircular canals. These canals are filled with fluid that shifts with movement. This sends impulses to the brain, which sends other impulses to muscles. The muscles help restore balance. If the movement is very rapid or unfamiliar, the semicircular canals cannot adjust quickly enough. Dizziness and nausea may result. Motion sickness is an example.

Hearing can be damaged by sharp objects like matches, toothpicks, hairpins and nails etc. If the ears are blocked, a doctor should be immediately consulted. Loss of hearing can occur due to long and repeated exposure to loud noises. The nerve cells in the ear detect air vibrations produced by sound waves and send these to the brain. Not all vibrations can be detected by human ear. Only which are 30 to 20k vibrations per second sounds can be detected by humans whereas animals have a far greater range of sounds.