1. Ear Today Gone Tomorrow

2. Main Components of the Hearing Mechanism
Outer Ear
Middle Ear
Inner Ear
Central Auditory Nervous System

3. Structures of the Outer Ear
Auricle (Pinna)
Collects sound
Helps in sound localization
Directs sounds to the eardrum

4. Tympanic Membrane “eardrum”
Forms boundary between outer and middle ear
Vibrates in response to sound

5. The Ossicular Chain A: Malleus (Hammer) B: Incus (Anvil)
C: Stapes (Stirrup)
Ossicles are smallest bones in the body
Vibrates when eardrum vibrates

6. Eustachian Tube connects middle ear to back of the throat
Equalizes air pressure
Normally closed except during yawning or swallowing
Not a part of the hearing process

7. Structures of the Inner Ear
Cochlea - Snail-shaped organ with a series of fluid-filled tunnels; converts mechanical energy into electrical energy

8. Vestibular System Consists of three semi-circular canals
Shares fluid with the cochlea
Controls balance
No part in hearing process

9. Hair Cells Frequency-specific High pitch sounds = base of cochlea
Low pitch sounds = apex of cochlea

10. Sound enters the ear and strikes the eardrum causing it to vibrate
The vibration is passed to the three middle ear bones (hammer, anvil, stirrup)
Vibrations create waves in the fluid found in the cochlea of the inner ear. Small hairs within the cochlea are bent sending an impulse to the auditory nerve
The auditory nerve sends information to the brain

11. Deafness failure of the three tiny bones to vibrate
The two main types of deafness
Conductive deafness
failure of the three tiny bones to vibrate
failure of the eardrum to vibrate
Nerve deafness
caused by disease, trauma
electrical impulses aren't able to reach the brain

12. Hearing Aids
The microphone picks up sounds from the environment and sends them to a processor that amplifies the signal (makes it louder)
After the sound is amplified, the receiver directs sound into the ear canal.