The inner ear begins where the stirrup hits the next membrane – known as the oval window.
Located in it are the organ of equilibrium and the cochlear. Approximately the size of a pea, the cochlear actually resembles a snail shell. It contains three canals filled with a liquid. Via one of these canals, the signals conducted into the liquid are directed to the tip and back via a second canal. The central canal is home to the actual organ of hearing, the organ of Corti.
The bottom of the organ of hearing is covered in thousands of tiny hairs – the hair cells. The wave movements in the liquid-filled canals change depending on frequency. The hair cells are only triggered when the amplitude is particularly great. The deeper the tones the further back in the cochlear the tiny hairs move, while high tones trigger the hair cells at the beginning of the cochlear. Wear of these tiny hairs is one of the main reasons for age related deafness.