How Sound Affects the Inner Ear

Figure 1

 

 

 

Diagram 1

The outer ear gathers  soundwaves and directs them through the ear canal.

Figure 2

 

 

 

Diagram 2

Soundwaves vibrate the eardrum, where the ossicles (middle ear bones) transmit the vibrations the the inner ear.

Figure 3

 

 

 

Diagram 3

Inside the inner ear, the cochlea, a spiral structure, contains fluid and about 30,000 highly sensitive hair cells, which respond to frequency (pitch) and intensity (loudness) of sound.

Figure 4

 

 

 

Diagram 4

Three rows of outer hair cells and one row of inner hair cells are connected to nerve fibers that translate sound as electrical signals to the brain.

Figure 5

 

 

 

Diagram 5 

Normal hair cells.

Figure 6

 

 

 

Diagram 6

Hair cells as they appear after permanent damage by excessive intensity or loudness of sound.

  

Watch a clip of this animated sequence (requires Windows Media Player)

For further information please contact Doug Plesh at 301-296-8730 or by e-mail at dplesh@asha.org.


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