Background

The inner ear contains the parts of the ear that transduce sound into a neural signal. In particular, the hair cells situated along the organ of Corti in the cochlea act by taking vibrations and converting them into a neural signal. In this way, the hair cells are equivalent to the rods and cones of the retinae. The cochlea is the snail-shaped structure of the inner ear that houses the hair cells that transduce sound into a neural signal. The term cochlea derives from the Greek word for snail. The cochlea is a coiled tube, coiled 2.74 times. As a coiled tube, it takes up just about 4 mm of space inside your ear, but if you were to unroll it, it would stretch to about 33 to 35 mm in length (1.3 inches).

In this activity, the cochlea will be unwound and only some of the structures are shown to make it easier to follow how the basilar membrane and cochlea function to transduce sounds. You can adjust the frequency and amplitude of the incoming sound to see how the basilar membrane responds differently as the characteristics of the sound change. In addition, you can focus on the cochlea,see how the sound moves through the ear from the tympanic membrane or, even, just examine the ossicles again.

Instructions

Full Screen Mode

To see the illustration in full screen, which is recommended, press the Full Screen button, which appears at the top of the page.

Illustration Tab

Settings

On the Illustration tab, you can adjust these parameters:

Play the Sound: check to start the animation and uncheck to stop the animation.
Frequency (Hz): adjust to see how the cochlea and basilar membrane respond to different frequencies.
Amplitude: make the sound more or less intense.
What Parts of the Ear to Show: Select what part of the ear you wish to examine: Ossicles, the Cochlea, or the Ear which shows the sound starting from the external auditory canal.

Reset

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.