Human heart. Computer-digitized image of the healthy human heart. Contours depict the structure of the heart and its blood vessels. The heart's muscular ventricles are at lower frame (blue). Deposits of fat (light yellow) surround the coronary arteries which supply blood to this region. At center left and right, the atria chambers of the heart are depicted as blue and yellow. Above center, large blood vessels are seen in different colors which supply the heart with deoxygenated and oxygenated blood respectively. The heart is positioned centrally in the chest, and acts as the muscular pump forcing blood around the body.