597The heart is a muscular pump containing four chambers connected by valves. Venous blood from your body flows through the superior and inferior vena cava into the right atrium, then through the tricuspid valve into your right ventricle. The right ventricle pumps blood through the pulmonary valve via pulmonary arteries into your lungs. From the lungs, blood enters the left atrium via the pulmonary veins and flows through the mitral valve into the left ventricle. The powerful left ventricle pumps oxygen-enriched blood through the aortic valve into the aorta for delivery to your body's tissues.
