FIGURE 2.

The cochlear battery facilitates sound detection. Sound waves deflect hair cell stereocilia, mechanically opening K+ channels and allowing potassium ions (K+) from the scala media to enter the hair cell. The subsequent depolarization of the hair cell activates voltage-gated calcium channels, which triggers a calcium influx that causes neurotransmitter to be released at the base of the hair cell. Neurotransmitter then diffuses into the nerve terminal and causes an action potential to be created in the spiral ganglion. This signal is then transmitted to the brain for auditory processing. The SV actively returns potassium ions that were used during this process to the scala media, maintaining the endocochlear potential and allowing for continuous sound detection.