The heart and how it works

The heart is a large muscle that pumps blood around your body. The blood delivers oxygen and nutrients around your body, and takes away carbon dioxide and waste products.

The heart is divided into four chambers:

  • Two chambers collect blood going into the heart. These chambers are called the right atrium and the left atrium.
  • Two chambers pump blood out of the heart. These chambers are called the right ventricle and the left ventricle.

There are four valves inside the heart. They open and close as the heart pumps. The valves keep the blood flowing in one direction through the heart.

The inside of the heart
The inside of the heart

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Blood travels from different parts of the body to the heart and back again through tubes called blood vessels. The blood going to the heart is low in oxygen. It travels through the heart and is pumped out to the lungs. In the lungs, the blood picks up oxygen and gets rid of carbon dioxide, which is then breathed out. The blood carrying oxygen travels back through the heart and is pumped out to the body again.

The outside of the heart
The outside of the heart

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Like the rest of your body, the heart needs its own blood supply to bring it oxygen and remove carbon dioxide. Small blood vessels on the outside of the heart carry blood and oxygen to the heart muscle. These are called coronary arteries.

The heart has its own electrical system that tells it when to beat and pump blood around the body. Cells called the sinus node send an electrical signal through the heart to start each beat. This happens about 60 to 100 times a minute.

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Heart problems

Different types of heart problem can develop if part of the heart is not working properly.

Warning signs of heart problems

If you have any warning signs of heart problems, tell your doctor straight away. Early treatment can prevent further damage.