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How the circulatory system works

Video - How blood is moved around the body

In this video, learn how blood moves around the body through the heart, arteries and more.

Find out about how blood delivers oxygen and nutrients to every cell in the human body

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What is the heart?

Illustration of a human heart
Image caption,
The heart is a muscle that pumps blood around the body. Your heart is in your chest.

The heart is a muscle. It pumps blood all around the body.

Illustration of a human heart
Image caption,
The heart is a muscle that pumps blood around the body. Your heart is in your chest.

What is blood?

Illustration of blood cells travelling through arteries
Image caption,
Blood travels around the body through blood vessels called arteries, capillaries and veins.

Blood is the transport system for our bodies.

It picks up and carries oxygen and nutrients to where they are needed. It also picks up waste products and helps transport them out of the body.

Blood is also part of the immune system. White blood cells fight off infections.

Illustration of blood cells travelling through arteries
Image caption,
Blood travels around the body through blood vessels called arteries, capillaries and veins.

How does the circulatory system work?

Illustration of the circulatory system of the human body, showing the heart, lungs, intestines and blood vessels
Image caption,
The heart pumps blood around the body through blood vessels. Blood transports nutrients from the intestines, oxygen from the lungs, and returns carbon dioxide to the lungs.

The left side of the heart pumps blood that contains oxygen around the body through arteries.

When blood passes the intestines, it picks up nutrients that have been absorbed from food.

Blood travel from arteries into capillaries. These deliver oxygen and nutrition to every cell in the body and pick up waste products including carbon dioxide.

Veins take the blood back to the right side of the heart. It is then pumped to the lungs.

The lungs absorb carbon dioxide and the blood absorbs oxygen. It then travels back to the left side of the heart, ready to be pumped around the body again.

The heart is so strong that this whole process only takes about one minute!

Illustration of the circulatory system of the human body, showing the heart, lungs, intestines and blood vessels
Image caption,
The heart pumps blood around the body through blood vessels. Blood transports nutrients from the intestines, oxygen from the lungs, and returns carbon dioxide to the lungs.
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