The Inner Ear – Structure and Function

By Mr. Bleecker and his Cat

Structure of the Ear

Outer Ear = Pinna

designed to gather and collect sound into the ear canal

Middle Ear – the Auditory Canal

Channels the sound toward the EAR DRUMChannels the sound toward the EAR DRUM

Middle Ear – the Ear Drum is actually called the “TYMPANIC MEMBRANE”

Sound waves = vibrations

HAMMER hits ANVIL moving the STIRRUP!

What Happens Next?

1. Sound waves travel into the SPIRALLED COCHLEA

2. Tiny hairs in the COCHLEA move to the beat, and send impulses along nerve fibres

3. All nerve fibres link to the AUDITORY NERVE, to the brain.

Inside the COCHLEA!

Eustacian Tube

Detectable Sound Levels – What can the Machinery Pick UP?

What Frequencies can we Hear?

2 000 - 20 000 Hz

100 000 – 140 000 Hz

Appearance of a Sound Wave

Detectable Sound Levels – What can be Heard?

Sound Wave Production

Levels of IntensitySoft (Low) Harsh(High)

Defeating Deafness – Cochlear ImplantsDefeating Deafness – Cochlear Implants

•The implant generates electric signals as the sound bounces off detector

•Vibrations = electricity

•Electricity stimulates the AUDITORY NERVE directly

Protect your Hearing! Ear plugs Ear – muffs Keep the volume

down

Spidey knows the Value of Protecting Your Hearing!Spidey knows the Value of Protecting Your Hearing!

1. Pinna = outer portion of ear used to collect sound waves

2. Auditory Canal = tube that sound travels down

3. Ear Drum = membrane that sends sound waves to hammer

4. Hammer = first of 3 bones. It vibrates, striking the anvil to carry on the sound

5. Anvil = gets hit by the hammer, striking the Stirrup

6. Stirrup = vibrates against OVAL WINDOW, carrying on sound

7. Cochlea = a spiral full of sensory “hairs,” which when bent, send an electrical signal to the AUDITORY NERVE

8. Auditory Nerve = carries all signals for sound to brain

9. SemiCircular Canals = full of gel-like material. Indicates if you are right side up or upside down.

(Balance)

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