1. Notes 21.3: The Ear

2. The Outer Ear consists of two main parts:
Pinna- collects the sound
Ear Canal - transfers the sound to the middle ear.
Because of its short length, the ear canal has a resonant frequency of about 2000 Hz.
This means that sounds of around 2000Hz sound louder than they actually are.

3. MIDDLE EAR:
Sound energy is lost as it moves from the outer ear (air) to the inner ear (liquid).
The function of the middle ear is to compensate for this loss by amplifying the sound energy.

4. Sound waves hit the Ear Drum and cause it to vibrate.
These vibrations are passed
along to 3 tiny bones (Ossicles) in this order:
Malleus - largest of 3
Incus - acts like a lever
Stapes - connected to Oval Window
The Eustachian Tube connects to the throat and equalizes the pressure on the Ear Drum (ears popping)

5. INNER EAR
Cochlea-tiny fluid filled organ with nerve cells that changes sound into a signal that is sent to the brain.
Cilia – tiny hair-like nerve cells in the cochlea.
Semicircular canal – sense of balance

6. 2 TYPES OF HEARING LOSS
Conductive – when the tissue surrounding the ossicles bones becomes less flexible.(aging)
Neurosensory – cilia become damaged. (aging, over exposure to noise)