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→Function - Hearing
tympanic membrane → ossicles → middle ear wall → middle ear cavity → oval window
tympanic membrane → ossicles → middle ear wall → middle ear cavity → oval window
*Amplification due to the bony lever is only 1.5times, as the stapedius muscle prevents the stapes from vibrating too much.
*Amplification due to the bony lever is only 1.5 times, as the stapedius muscle prevents the stapes from vibrating too much.
*The tympanic membrane is 20 times larger than the oval window.
*The tympanic membrane is 20 times larger than the oval window.
===The Cochlea===
===The Cochlea===
*Displacement of the basilar membrane during sound transmission is 200 times that of the tympanic membrane.
*Displacement of the basilar membrane during sound transmission is 200 times that of the tympanic membrane.
*This is due to the relative inertia of the tympanic membrane, so it remains relatively still as the basilar and hair cells move relative to it.
*This is due to the relative inertia of the tympanic membrane, so it remains relatively still as the basilar and hair cells move relative to it.
===The Hair Cell Receptor===
===The Hair Cell Receptor===
This shows that if the cilia is pushed in one direction, it will be excited, but if pushed in the other direction it will be inhibited.
This shows that if the cilia is pushed in one direction, it will be excited, but if pushed in the other direction it will be inhibited.
===Hair Cell Resting Potentials===
===Hair Cell Resting Potentials===
*Cilia are in endolymph, but hair cell body is in perilymph.
*Cilia are in endolymph, but hair cell body is in perilymph.
*There is a high concentration of potassium ions (K+) in endolymph, which is maintained by ion pumps in the stria vascularis.
*There is a high concentration of potassium ions (K+) in endolymph, which is maintained by ion pumps in the stria vascularis.
===Cochlear Microphonics===
===Cochlear Microphonics===
*Non-nervous: no latency, refractoriness, and persists after death.
*Non-nervous: no latency, refractoriness, and persists after death.
*Generated by hair cells.
*Generated by hair cells.
===Tone===
===Tone===
3. '''Phase Locking''': allows extremely fine discrimination of pitch within the musical range. The action potential occurs at a particular point in the sound wave. The brain can determine frequency information from this.
3. '''Phase Locking''': allows extremely fine discrimination of pitch within the musical range. The action potential occurs at a particular point in the sound wave. The brain can determine frequency information from this.
===Direction Discrimination===
===Direction Discrimination===