How hearing works

How hearing works

Although hearing is the process of sound travelling through the outer, middle and inner ear, it's the brain that interprets what is heard.

Each part of the ear plays an essential role in transmitting sound.

• Outer ear – the part which can be seen (the pinna) and the ear canal.

• Middle ear – the eardrum and three tiny connected bones (ossicles), which are often called the hammer, anvil and stirrup.

• Inner ear – the snail-shaped cochlea and the hearing nerve, as well as semi-circular canals that help with balance.

 

1. Sound waves enter the outer part of the ear and travel along the ear canal to the eardrum.
2. The movement of the eardrum vibrates the ossicles in the middle part of the ear.
3. These vibrations are transmitted to an organ filled with liquid; the inner ear called the cochlea.
4. The tiny cilia lining the cochlea pick up this movement and send signals to the auditory nerve and then to the brain, where they are interpreted as sound.

Natural hearing depends on these parts working together. Hearing loss may occur when one of these parts has problems.

Hearing, communication and brain function

Hearing may be regarded as the first step in developing communications skills. It is thought that children learn to recognise a parent because as babies they begin to notice sounds in the womb. Hearing can be seen as a key part of learning to talk as children can learn by mimicking sounds.

Although hearing is not the only form of communication, hearing loss may affect speech and interaction.

For older people, hearing loss may be accompanied by other problems, including an inability to think clearly or remember. Hearing with both ears may help with understanding and locating the source of sounds.²