Consumer Guide 2 - Page 4

How Do We Hear? Sound enters the ear canal as pressure waves of varying pitch and volume. Where ear wax is secreted These waves pass down the ear canal and beat on the ear drum Ear canal causing it to vibrate. Balance organ The ear drum sends Middle ear cavity these vibrations to the Inner ear three middle ear bones which in turn vibrate against the hearing organ known as the Pinna Cochlea. Ear drum In the Cochlea the travelling sound wave stimulates specific sensory cells (called Eustachian tube hair cells) according to the pitch and volume of the sound signal. This in turn triggers an electrical impulse along the although it is known that auditory nerve to the brain. hearing activates more areas of the brain than any other sense. So it is In fact we are still discovering how much very important to preserve and protect hearing activates new parts of the brain, this most important ability. 4