Our ears are full of sensitive hair cells that allow us to hear. Exposure to noise can damage these cells and they can't be repaired.
Your ears have three sections: the outer ear, the middle ear and the inner ear. The 'pinna' is the part of the ear you can see on the side of your head.
The outer ear consists of the pinna - the part you can see on the side of your head - and the external auditory canal - the passage that sounds travels along. The eardrum covers the other end of the canal. When sound reaches the eardrum from the outside, it vibrates. Beyond the eardrum is the middle ear.
You need your ears to hear but your body also uses them to keep your balance.
The middle ear is a cavity filled with air. A chain of three tiny bones stretches across the cavity to conduct sound from the eardrum to the 'oval window', which leads to the inner ear. When sound enters your ears and makes the eardrum vibrate, the vibrations pass from the eardrum along the bones. One of the bones is called 'the stapes'. The stapes pushes like a piston against the membrane in the oval window, sending sound vibrations into the fluid of the cochlea in the inner ear.
The cochlea is the hearing part of the ear. It is a fluid-filled spiral tube. The cochlea is lined with thousands of tiny hair cells. When sound waves enter the fluid of the cochlea, they move the tiny hairs, causing the hair cells to send electrical messages to the auditory or hearing nerve. Different frequencies of sound are picked up by different hair cells. The nerve passes impulses up to your brain, which recognises them as different sounds - for example your favourite band, people talking or footsteps.