From the right atrium, the venous blood passes through a valve into the right ventricle. From the right ventricle, the venous blood is carried through the pulmonary artery up to the lungs to be oxygenated or purified. The left atrium receives the purified blood through the pulmonary vein. From the left atrium the purified blood passes through a valve into the left ventricle. From the left ventricle, the aorta sends the arterial blood to all parts of the body, except the lungs.
Cycle is repeated when venous blood is brought back to right atrium.
Adult body contains about l5 pints of blood Function. Carries oxygen, water, food and secretions to all cells. Carries away carbon dioxide and waste products to be eliminated through excretory channels. Helps to equalize body temperature, protecting body from extreme cold or heat. Aids in protecting the body from harmful bacteria and infections through the action of the white blood cells.