How do sound vibrations reach the cochlea?
Sound waves cause the thin skin of the eardrum to vibrate. This vibration, in turn, vibrates a chain of three tiny bones which are attached, at one end of the chain, to the eardrum, and at the other end of the chain, to a thin drumlike structure on on the opening to the cochlea. The vibration of this “round window” as it is called, causes the fluid inside the cochlea to flow, which in turn causes tiny hairs inside the cochlea to move. These hairs, when moved, send signals to the brain which are interpreted as sound.
