Blood flow through the heart

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Blood flow through the heart

These illustrations show the heart from the front. The right side of the heart is on the left side of the heart illustrations. The left side of the heart is on the right side of the illustrations.

The heart has four chambers that pump blood. The chambers are called the right atrium, right ventricle, left atrium, and left ventricle. The right and left sides of the heart are separated by a muscular wall called the septum. This prevents blood without oxygen from mixing with blood that has oxygen. The heart also has valves that separate the chambers and connect to major blood vessels.

Blood flows from the body into the right atrium. The blood on the right side of the heart has been used by the body and has little oxygen left in it (is deoxygenated or oxygen-poor).

• The oxygen-poor blood flows from the right atrium through the tricuspid valve to the right ventricle.
• From the right ventricle, blood is pumped through the pulmonary valve into the blood vessel that goes to the lungs. This blood then picks up oxygen (becomes oxygenated or oxygen-rich).

Oxygen-rich blood flows from the lungs through blood vessels back to the heart's left atrium.

• From the left atrium, blood goes through the mitral valve and into the left ventricle.
• The left ventricle pumps blood through the aortic valve to a major blood vessel called the aorta and out to the body.

The blood delivers oxygen to the body, then returns through veins to the right atrium and repeats the blood flow cycle.

Credits

Last updated:	October 27, 2005
Reviewed By:	Michael J. Sexton, MD - Pediatrics, Larry A. Latson, MD - Pediatric Cardiology