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A model of a human heart on display, showcasing the intricate structure and functions.

How your heart works

Your heart

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How your heart works

Stucture and function of the heart

Your heart is a muscle that pumps blood and oxygen to all parts of your body. Your heart also has its own blood supply.

Your heart is a vital organ. The functions of the heart are to:

  • pump blood and oxygen around the body
  • deliver waste products (carbon dioxide) back to the lungs so they can be removed.

The heart consists of four chambers which are connected by valves. Valves direct the flow of blood to big blood vessels. Blood travels in these blood vessels to deliver oxygen all around the body. Blood vessels also carry blood back to the lungs to remove waste and to put more oxygen in the blood.

The heart also has its own blood supply. Coronary arteries supply blood and oxygen to the heart muscle. When the coronary arteries become blocked, oxygen can’t reach the heart muscle. This can cause chest pain (angina) or a heart attack.

Explore the heart

Click on the dots in the pictures below.

  • The picture on the left shows the coronary arteries which wrap around and into the heart muscle.
  • The picture on the right shows the inside of the heart. You can see the four chambers, heart valves and major blood vessels.
Coronary arteries
Chambers and blood vessels
Explore the heart by selecting a dot

Right coronary artery The right coronary artery supplies blood to the right side of the heart. It also supplies blood to the nodes that control your heart’s rhythm (sinoatrial node and atrioventricular node).

Left main
coronary artery The left main coronary artery supplies blood to the left side of the heart muscle.

Left circumflex artery The circumflex artery branches off from the left main coronary artery. It supplies blood to the back of the heart.

Left anterior descending branch The left anterior descending artery branches off the left main coronary artery and supplies blood to the front of the heart.

Explore the heart by selecting a dot

Vena cavae The large veins that carry deoxygenated (low oxygen) blood from your body into the heart.

Aorta The aorta is the largest artery in the body. It carries oxygenated (high oxygen) blood from your heart to your body.

Right atrium The chamber that receives blood from your vena cava before pumping it into your right ventricle (lower chamber).

Left atrium The chamber that receives blood from your lungs before pumping it into your left ventricle (lower chamber).

Right ventricle This chamber pumps the blood to your lungs to get more oxygen into your blood.

Left ventricle This chamber of the heart pumps oxygenated (high oxygen) blood into your aorta. It is the largest chamber in your heart.

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Last updated15 January 2024