Image Description:

Direction of Blood Flow through the Heart

This illustration shows the direction of blood flow through the heart. Blood flows through the heart in a continuous loop, constantly cycling between the lungs and the rest of the body. Here is how that journey unfolds in seven steps.

Oxygen-depleted blood from the body returns to the heart through two large veins the superior vena cava, draining the upper body, and the inferior vena cava, draining the lower body. This blood enters the right atrium, the heart's upper-right chamber, which squeezes it through the tricuspid valve down into the right ventricle below. The right ventricle then contracts, driving the blood through the pulmonary valve and into the pulmonary artery, the only artery in the body that carries oxygen-poor blood.

The pulmonary artery delivers this blood to the lungs, where it releases carbon dioxide and absorbs a fresh supply of oxygen. Now oxygen-rich, the blood travels back to the heart through the pulmonary veins and arrives in the left atrium. From there it passes through the mitral valve into the left ventricle the heart's most powerful chamber. The left ventricle contracts forcefully, pushing the oxygenated blood through the aortic valve and into the aorta, the body's main artery, which distributes it to every organ and tissue in the body. The cycle then begins again.

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Anatomy Visible in the Medical Illustration Includes:

heart, ventricle, chamber, atrium, aorta, pulmonary, vein, inferior vena cava, artery, blood, flow.

Image created by:

Joanna Culley