When a vibration of the basilar membrane causes the basilar membrane to move upward, the stereocilia brush spread apart. When stereocilia are pushed in this manner, there is a change in the cell’s voltage potential. This voltage change causes the release of neurotransmitters, which cause the auditory nerve to send a signal. And with the induction of a signal in the auditory nerve, the sound has been transduced and sound information gets conveyed to the brain.
In this activity, you can observe the motion of a single hair cell and see how the motion leads to transduction, or the conversion of the sound stimulus into action potentials in the brain.
To see the illustration in full screen, which is recommended, press the Full Screen button, which appears at the top of the page.
On the Illustration tab, you can adjust these parameters:
Play the Sound: check to start the animation and uncheck to stop the
What Parts of the Ear to Show: Select what part of the ear you wish to examine: the Cochlea, or a single Hair Cell.
Show Vertical Movement: when only a single hair cell is shown, allow or not the vertical motion of the hair cell that results from the basilar membrane.
Show Rotation: when only a single hair cell is shown, show the rotation of the hair cell that results from the basilar membrane.
Frequency (Hz): adjust to see how the cochlea and basilar membrane respond to different frequencies.
Amplitude: make the sound more or less intense.
Speed of animation: change the update rate of the animation.
Pressing this button restores the settings to their default values and allows you to adjust speed and relative size. It also resets the counter before you can indicate if you have the objects arriving at the same time.