The heart requires its own constant blood supply in order to keep beating and this is delivered through the coronary arteries. Genetic and lifestyle factors can lead to the coronary arteries becoming blocked, and an increased risk of heart disease.The circulatory system

The circulatory systemBlood carries oxygen and nutrients to the bodyscells, and waste products away from them. The circulatory system consists of: the heart, which is the muscular pump that keeps the blood moving the arteries, which carry blood away from the heart the veins, which return blood to the heart the capillaries, which are tiny blood vessels that are close to the bodys cells.The diagram outlines the circulatory system. To make things clear, oxygenated blood is shown in red, and deoxygenated blood in blue.