Normal Blood Flow

The heart is in charge of pumping blood to the lungs and to the body. Normally, blue blood (eg deoxygenated blood, or blood without oxygen) returns from the body via the inferior and superior vena cava to the right atrium. (See Normal heart anatomy).  From there, the blue blood passes into the right ventricle where it is then pumped out to the lungs to receive oxygen. The presence of oxygen in the blood turns the blood a more red color ("red" or oxygenated blood). Red blood returns from the lungs to the left atrium and then passed into the left ventricle. The left ventricle then pumps the red blood out the aorta to the body so that the oxygen can be delivered to the tissues.