| | | | | like a tiny shell. The cochlea, which is a coiled spinal |
| The outer ear, which is the part you see on the side of | | | | tube is full of liquid and contains thousands of very |
| your head, collects sounds in the form of vibrations in | | | | fragile hair like nerve cells which convert the vibrations |
| the air. These vibrations change depending on the | | | | from the stirrup into electrical impulses. When the |
| frequency of the sound. Higher frequencies i.e. opera | | | | vibrations from the stirrup reach the fluid in the cochlea, |
| singers, create much quicker vibrations, whereas lower | | | | they make the hair cells vibrate. Each hair cell has a |
| frequencies, such as speech, the vibrations will be | | | | natural response to different vibrations allowing you to |
| much slower. These sound waves, in the form of | | | | hear a wide variety of sounds at different |
| pressure waves, travel down the ear channel to the | | | | frequencies. These electrical impulses pass along the |
| eardrum. The eardrum is a very thin membrane | | | | auditory nerve to the brain. When these electrical |
| located between the ear channel and the middle ear. | | | | impulses reach the brain, it translates the signals into |
| When the sound waves strike the eardrum it causes it | | | | different information e.g. music, speech etc. |
| to vibrate at the same frequency as the sound waves | | | | The ear has a second function, which is not used for |
| striking it. | | | | hearing, these are the semi-circular canals. These |
| A chain of small interconnected bones – the | | | | canals form an important part in your balance system; |
| hammer, anvil and stirrup, are connected between the | | | | they are filled with fluid and small hairs which send |
| eardrum and the inner ear. Vibrations on the eardrum, | | | | signals to your brain enabling you to maintain balance. |
| which is connected to the hammer, will set the anvil | | | | Loss of hearing can be caused by damage through |
| and stirrup into motion at the same frequency as the | | | | accident, infection, hereditary or constant loud noises. |
| sound waves entering the outer ear. The three bones | | | | This can also result in tinnitus or vertigo. Most problems |
| of the middle ear act together forcing the stirrup to | | | | associated with the outer ear are caused by a |
| vibrate up to 15 times larger than the vibrations on the | | | | blockage of the ear channel by wax, swelling through |
| eardrum. Because of this feature, sounds that are | | | | infection of the presence of a foreign body. Middle ear |
| very faint can still be heard. The middle ear cavity is | | | | problems are mainly caused by abnormalities of the |
| also connected to the nose and throat by the | | | | bone structure i.e. where the bones fuse together. This |
| Eustachian tube, this is why you swallow when going | | | | will normally have to be cured by surgery. Inner ear |
| up in an aeroplane to equalise the pressure on the | | | | problems are almost entirely caused by excessive |
| eardrum. Also when you have a cold and the | | | | exposure to intense noise which can cause permanent |
| Eustachian tube becomes blocked, the ear cavity is | | | | hearing loss and also tinnitus. This damage is not |
| not able to equal the pressure, causing earache. | | | | repairable and will result in having to wear a hearing aid. |
| The inner ear contains the cochlea, which is shaped | | | | |