How the ear works

Our ears are very clever things, responsible for our
hearing and balance.
So how do they work?

Structure of the ear

The ear is made up of three sections:

1. The outer ear

The outer ear consists of the pinna (the part you can see on the side of your head) and the ear canal (the passage that sound travels along). The eardrum covers the other end of the canal and vibrates when sound reaches it.

2. The middle ear

The middle ear is an air-filled cavity behind the eardrum that’s home to a chain of three tiny bones, called the ossicles (malleus, incus, and stapes). These bones stretch right across the middle ear to conduct sound from the eardrum to the inner ear.

3. The inner ear

The inner ear contains the cochlea, a fluid-filled spiral tube, which receives the sound vibrations from the middle ear. The cochlea is lined with thousands of tiny hair cells that are moved by sound waves coming into the ear. Their movement causes electrical messages to be sent the auditory nerve – the link between the ear and the brain.

Which part of the ear is used as a balance mechanism for the body?

There is a section of the inner ear called the semi-circular canals which are a major contributor towards our balance system. They are filled with a special fluid that 'swirls' around in response to movement, activating some very specialist nerve receptor cells which communicate with our brain to tell us how we are moving. The other parts of our body involved in balance are our eyes (which tell us where we are in relation to the horizon) and our feet (which tell us which direction our body is leaning in).

How do we hear sound?

The outer ear is the organ outside the head. Its intricate shape collects sound waves and funnels them into the ear canal and then onto the eardrum, which separates the outer and inner ear. The membrane of the eardrum is taut, like a drum skin, and vibrates in response to the sound waves.

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These vibrations then pass on to three tiny bones in the middle ear known as the hammer, anvil and stirrup. These bones are responsible for transmitting sound waves from the eardrum to the inner ear. The stirrup vibrates against a membrane, which sends pressure waves through the cochlea in the inner ear.

Inside the cochlea – which is the size of a pea and shaped like a snail shell – thousands of hair-like cells, linked to nerve fibres, change the sound waves into electrical signals, which are passed on to the brain.

What is hearing loss?

Our ears are highly sensitive and it’s very common for hearing to be affected over time, for a number of reasons. The types of hearing loss vary and depend mainly on which part of the hearing system is affected. Find out about the different types of hearing loss and what we can do to help you make the right choices when it comes to your hearing.

Understanding hearing loss

Signs of hearing loss