The Circulatory System Circulatory System in anatomy and physiology. The course taken by the blood through the arteries, capillaries, and veins back to the heart. In humans and the higher vertebrates, the heart is made up of four chambers. The right and left auricles, or atria, and the right and left ventricles. The right side of the heart pumps oxygen poor blood from the cells of the body back to the lungs for new oxygen. The left side of the heart receives blood rich in oxygen from the lungs and pumps it through the arteries to the various parts of the body. Pulmonary circulation, blood from the entire body is transported to the right atrium