stereocilia

Stereocilia are tiny, hair-like structures found on sensory hair cells in the inner ear. They are made of bundles of actin filaments and are arranged in rows of varying lengths, resembling a brush. When sound vibrations or head movements occur, these structures bend, triggering nerve signals that are sent to the brain, allowing us to hear and maintain balance. Stereocilia are critical for translating mechanical stimuli into electrical signals, but they do not move freely like hair; instead, their bending opens ion channels that initiate neural communication.