How we Hear
Function of the ear
The ear is a very complex organ comprising three parts: the outer ear, the middle ear and the inner ear. From the inner ear the auditory nerve transmits information to the brain for processing.
a) The outer ear
The outer ear includes the auricle, the auditory canal and the eardrum. It funnels sounds from the surrounding environment into the hearing system. The auricle helps to gather the sound waves, and the auditory canal then directs them to the eardrum.
b) The middle ear
The middle ear is an air-filled cavity which contains the smallest bones in the human body - the malleus, incus and stapes. These are connected to the eardrum on one side, and on the other side to a thin membrane-covered opening on the wall of the inner ear. The middle ear is also connected to the throat via the Eustachian tube, which keeps the air pressure in the middle ear equal to that of the surrounding environment.
c) The inner ear
In the inner ear the auditory input is processed by the cochlea, while information affecting balance is processed by the semicircular canals. Along the entire length of the fluid filled cochlea there are tiny hair cells. These hair cells are bent when the fluid is displaced by sound waves passed on by the middle ear bones. This triggers a chemical response, which activates the corresponding nerve endings. These then transmit the message to the area of the brain in charge of interpreting auditory input.
Hearing is a Precious Gift
Stop and think for a moment about the sounds that enrich our lives:
- the whispered words of a toddler,
- the singing of birds
- the voices of friends and loved ones
- the rustling of wind in the trees
- the music of a symphony orchestra.
Our ability to hear these sounds is a vital part of enjoying life. Hearing loss can inhibit a person's ability to experience the sounds around them. And, this affects not only their lives, but also the lives of family and friends.
Millions of People Have Difficulty Hearing
- "What did you say?"
- "Everyone seems to mumble."
- "I can hear but I can't understand."
- "My children tell me I watch TV with the volume too loud."
- "Some words sound alike and it's hard to tell them apart."
Do you find yourself or someone you know making these comments? You're not alone. Millions of Canadian's have a hearing loss. The following information contains basic information about hearing, its importance, ways in which it can be damaged, and, most importantly, what kinds of help are available.