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How does the human cardiovascular system transport oxygen and nutrients to body tissues?

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Silhouette diagram of the human body highlighting the heart and major blood vessels, with labeled arteries in red and veins in blue to show the structure of the cardiovascular system. — Circulatory system Human circulatory system.

The human cardiovascular system transports oxygen and nutrients to body tissues through a process known as systemic circulation. Driven by the pumping force of the heart, oxygenated blood is ejected from the left ventricle into the aorta, the body's largest artery.12

From the aorta, blood travels through a branching network of arteries and smaller arterioles to reach the capillaries. These microscopic vessels, which have walls only one cell thick, act as a semipermeable membrane that facilitates the exchange of substances. At the arteriolar end of the capillary unit, oxygen and nutrients—such as glucose, fatty acids, and vitamins—pass into the surrounding tissues.234

This transport is essential for maintaining homeostasis and supporting organ function. Once the exchange is complete, the blood, now carrying carbon dioxide and metabolic waste products, flows into venules and veins to return to the heart’s right atrium, where it will eventually be sent to the lungs for re-oxygenation.21