How do hearing and balance receptors in the ear work?

Hearing and balance receptors in the ear work by converting sound waves and head movements into electrical signals.

The ear is a complex organ that serves two main functions: hearing and balance. Both of these functions rely on the conversion of physical stimuli into electrical signals that the brain can interpret. This process is known as transduction.

For hearing, this process begins when sound waves enter the ear and hit the eardrum, causing it to vibrate. These vibrations are then transferred to the three small bones in the middle ear: the malleus, incus, and stapes. The stapes bone pushes on the oval window, a membrane that separates the middle ear from the inner ear, causing fluid in the cochlea to move. This movement of fluid causes the hair cells in the cochlea to bend. As these hair cells bend, they open ion channels that allow potassium and calcium ions to enter the cell. This influx of ions generates an electrical signal that is sent to the brain via the auditory nerve.

Balance, on the other hand, is maintained by the vestibular system in the inner ear. This system consists of three semicircular canals and two otolith organs, the utricle and saccule. The semicircular canals detect rotational movements of the head, while the otolith organs detect linear movements and the force of gravity. Similar to the cochlea, these structures contain hair cells that bend in response to movement. When the head moves, fluid in the semicircular canals or otolith organs moves, causing the hair cells to bend and open ion channels. Again, this influx of ions generates an electrical signal that is sent to the brain via the vestibular nerve. The brain then interprets these signals to maintain balance and spatial orientation.