1. The Ear Biology 12

2. What is sound? A form of energy which travels in the form of a wave. A form of energy which travels in the form of a wave. The outer ear or pinna collects the sound and directs it into the auditory canal. The outer ear or pinna collects the sound and directs it into the auditory canal. Hearing begins when sound waves hit the ear drum a.k.a. the tympanic membrane. Hearing begins when sound waves hit the ear drum a.k.a. the tympanic membrane. These vibrations are passed on to the 3 bones of the middle ear. These vibrations are passed on to the 3 bones of the middle ear.

3. The Middle Ear They are called: They are called: Malleus or hammer Malleus or hammer Incus or anvil Incus or anvil Stapes or stirrup Stapes or stirrup These bones concentrate and amplify the vibrations.

4. The Middle Ear

5. The Inner Ear The cochlea is shaped like a snail shell and is filled with fluid. The cochlea is shaped like a snail shell and is filled with fluid. The cochlea is lined with cilia which react to the fluid vibrations and converts them into electrical impulses. The cochlea is lined with cilia which react to the fluid vibrations and converts them into electrical impulses.

6. Temporal Lobe of Cerebrum The nerve impulses created in the cochlea travel via the auditory nerve to the temporal lobe of the cerebrum. The nerve impulses created in the cochlea travel via the auditory nerve to the temporal lobe of the cerebrum. The brain interprets this information as sound. It can distinguish pitch and loudness. The brain interprets this information as sound. It can distinguish pitch and loudness.

7. Balance and the Inner Ear Did you know that keeping your balance is the job of the inner ear? A structure made of 2 canals is filled with a gel like substance. When you bend forward, this gel slips ahead and bends little cilia to let you know that you are off balance. When your head is upright, the cilia do not move and you feel balanced.

8. Class Activity Biology 12 Text Biology 12 Text Page 449 Page 449 In small groups, read the case study. In small groups, read the case study. Prepare a list of points. Prepare a list of points. Answer questions a) and b). Answer questions a) and b). Suggest improvements and prepare to defend your viewpoint in class. Suggest improvements and prepare to defend your viewpoint in class.