How Does a Normal Heart Work?

The heart consists of four chambers. The top two chambers (atria) receive blood while the bottom two chambers (ventricles) pump blood out.

Deoxygenated venous blood returns to the right atrium of the heart. Blood flows from the right atrium to the right ventricle by the opening of the tricuspid valve. Blood is prevented from going backward into the atrium by the closure of the tricuspid valve. The right ventricle then contracts and pumps blood out through the pulmonary valve into the pulmonary artery. The pulmonary valve is closed and the blood is sent to the lungs where it picks up oxygen.

Oxygenated blood returns from the lungs by the pulmonary veins and enters the left atrium. From the left atrium, blood enters the left ventricle by the opening of the mitral valve. Blood is prevented from flowing back into the left atrium by the closure of the mitral valve. Blood is then pumped out the left ventricle to the aorta by the opening of the aortic valve. Blood is prevented from flowing back into the left ventricle by the closure of the aortic valve. From the aorta, oxygenated blood is pumped out to the entire body.

Animation showing a normal functioning heart