How the Body Works : Inside the Heart

Inside the Heart

The heart is a muscular pumping organ which beats nonstop to circulate blood around the body. It functions as two halves, each consisting of a holding chamber, or atrium, and a pumping center, or ventricle. After circulating around the body, blood, now deoxygenated, returns to the right atrium through large veins, the superior vena cava and the inferior vena cava. When the atrium is full, blood is forced through the tricuspid valve into the right ventricle. It is then pumped to the lungs through the pulmonary valve into the pulmonary artery. The oxygenated blood returns via the pulmonary veins to the left atrium. After flowing through the mitral valve it is pumped out of the left ventricle into the aorta to return to the general circulation.