The heart pumps oxygen-rich blood through arteries throughout the body. Blood carries oxygen and other nutrients that the body needs. coronary heart disease Caused by fat accumulation in the inner layer of coronary arteries. These blood cells are located outside the heart and carry blood to the heart, myocardium. These sebum deposits may build up during adolescence and gradually. thicker and larger throughout life This thickening, known as atherosclerosis (hardening of the arteries), narrows the arteries and can narrow or block blood flow to the heart.