The inner ear begins where the stirrup hits the next membrane – known as the oval window - which contains the organ of equilibrium and the cochlear.
The cochlear resembles a snail shell and is approximately the size of a pea. It contains three canals filled with a liquid.
The first canal directs the signals conducted into the liquid 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 is covered in thousands of tiny hairs.
The wave movements in the liquid-filled canals change depending on frequency. The hairs are only triggered by loud noises. 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.
Damage or “wear” of these tiny hairs in the cochlear is one of the main reasons for age related hearing loss.