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Hearing
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Hearing is an extremely complex system and is the first of the five senses to develop in the foetus and to enable contact with the world. |
The key element of this system is the ear, which picks up sound, translates it into electrical impulses and transmits it along the auditory nerve to the brain where it is read and interpreted. To understand more, imagine entering this organ and 'visiting' its various parts.
Outer ear
This includes the auricle, commonly called ear - which helps us determine where the sound comes from - then the auditory canal, and lastly the eardrum. When sounds reach the membrane (eardrum) they are transformed by it into vibrations which are transmitted to the middle ear.
Middle ear
In just one square centimetre the middle ear contains the human bodies three smallest bones: hammer, anvil and stirrup. Their movement, caused by the eardrum, is amplified up to twenty times, thus transmitting to the inner ear all the sophisticated richness of sounds, from the single tone to those of an entire request.
Inner ear
In a small structure called the cochlea are the ciliary cells (twenty thousand per ear) capable of sharing tasks: some working with loud sounds, others with weak sounds. The ciliary cells are responsible for a further transfer of sounds, from vibrations to electrical impulses, which reach the brain along the slender fibres of the auditory nerve, where they determine the sensation of hearing.
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