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What is the circulatory system?

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Quick answer

The circulatory system is the body's transport network — the heart, blood, and blood vessels — that carries oxygen, nutrients, and waste around the body. The heart pumps blood through arteries, capillaries, and veins in a continuous loop. The heart pumps blood through a network of vessels.

Key things to understand

  1. The heart pumps blood through a network of vessels.
  2. Arteries carry blood away from the heart; veins return it.
  3. Tiny capillaries exchange oxygen, nutrients, and waste with cells.
  4. It delivers oxygen and removes carbon dioxide continuously.

People also ask

What does the circulatory system do?
It transports oxygen, nutrients, hormones, and waste throughout the body via blood.
What are arteries, veins, and capillaries?
Arteries carry blood from the heart, veins return it, and capillaries exchange materials with cells.
How is it linked to the lungs?
Blood picks up oxygen in the lungs and drops off carbon dioxide, then circulates the oxygen to the body.

Part of the guide: How Your Body Works →