KEY POINTS

1. Sound waves are alternating phases of condensation and rarefaction (pressure waves) of molecules in the external environment.

2. Outer and middle ears funnel sound waves to the cochlea.

3. The cochlea is located in the inner ear.

4. The cochlea transduces sound waves to action potentials of the eighth cranial nerve.

5. Deciphering of sound wave frequency begins in the cochlea.

6. Action potentials from the cochlea are transmitted up through the brainstem to the cerebral cortex.

7. Deafness results from an interruption in the hearing process.