The outer ear, which is the part you see on the side of your head, collects sounds in the form of vibrations in the air. These vibrations change depending on the frequency of the sound.  Higher frequencies i.e. opera singers, create much quicker vibrations, whereas lower frequencies, such as speech, the vibrations will be much slower. These sound waves, in the form of pressure waves, travel down the ear channel to the eardrum. The eardrum is a very thin membrane located between the ear channel and the middle ear. When the sound waves strike the eardrum it causes it to vibrate at the same frequency as the sound waves striking it.

A chain of small interconnected bones – the hammer, anvil and stirrup, are connected between the eardrum and the inner ear. Vibrations on the eardrum, which is connected to the hammer, will set the anvil and stirrup into motion at the same frequency as the sound waves entering the outer ear. The three bones of the middle ear act together forcing the stirrup to vibrate up to 15 times larger than the vibrations on the eardrum. Because of this feature, sounds that are very faint can still be heard. The middle ear cavity is also connected to the nose and throat by the Eustachian tube, this is why you swallow when going up in an aeroplane to equalise the pressure on the eardrum. Also when you have a cold and the Eustachian tube becomes blocked, the ear cavity is not able to equal the pressure, causing earache.

The inner ear contains the cochlea, which is shaped like a tiny shell. The cochlea, which is a coiled spinal tube is full of liquid and contains thousands of very fragile hair like nerve cells which convert the vibrations from the stirrup into electrical impulses. When the vibrations from the stirrup reach the fluid in the cochlea, they make the hair cells vibrate. Each hair cell has a natural response to different vibrations allowing you to hear a wide variety of sounds at different frequencies.  These electrical impulses pass along the auditory nerve to the brain. When these electrical impulses reach the brain, it translates the signals into different information e.g. music, speech etc.

The ear has a second function, which is not used for hearing, these are the semi-circular canals. These canals form an important part in your balance system; they are filled with fluid and small hairs which send signals to your brain enabling you to maintain balance. Loss of hearing can be caused by damage through accident, infection, hereditary or constant loud noises. This can also result in tinnitus or vertigo. Most problems associated with the outer ear are caused by a blockage of the ear channel by wax, swelling through infection of the presence of a foreign body. Middle ear problems are mainly caused by abnormalities of the bone structure i.e. where the bones fuse together. This will normally have to be cured by surgery. Inner ear problems are almost entirely caused by excessive exposure to intense noise which can cause permanent hearing loss and also tinnitus. This damage is not repairable and will result in having to wear a hearing aid.