Cochlea of ear. Light micrograph of a cross section through the fluid filled canals of the cochlea in the inner ear. Noise vibrations in the fluid in the canal at the top (white) cause vibrations in the vestibular membrane (line crossing the canal). These in turn create vibrations in the organ of Corti (centre right, grey) that responds to pitch and loudness. The tectorial membrane (grey semicircle) vibrates and stimulates the very sensitive hair cells on the basal membrane (pink). Spiral ganglia (purple, centre left) are nerve cells that relay the message to the brain. At the left and right of the section are bone (blue).