Coronary arteries - image description

The illustration shows a cross section of two blood vessels. The artery walls are shown and in each blood vessel an arrow indicates the flow of blood through the vessel. In the normal artery, the blood flows easily along the blood vessel. In the narrowed artery, there is an area of fatty tissue attached to the inside of the artery wall. The blood flow in the narrowed artery is abnormal as it has to go under the fatty tissue.