The Heart

The heart muscle is the size of a fist, and an incredibly efficient pump! It pumps around 300 litres of blood around your body every hour. That's around 2.7 million litres a year!

The heart uses rhythmic contractions to pump blood around the body via the blood vessels. When the heart beats, a pressure builds. This is known as blood pressure. Your heart is roughly the same size as your fist and is located behind the thorax between the lungs. The heart is made up similar powerful striped muscles as those found in the thigh. However, you cannot control the way the heart moves.

The heart has two cavities that are separated by a tight partition. Each side contains an atrium where blood collects, and a chamber that pumps the blood away. There are flaps between each cavity that open and close as the heart contracts.

How it works:

The right atrium receives blood from the right vena cava. From here, the blood is pumped into the right chamber, which then pumps the blood to the lungs where it is oxygenated.

The oxygenated blood is then taken by the left atrium and is pumped into the aorta or the aorta in the left chamber. The greatest force pumps the oxygenated blood around the body. Therefore, the muscle wall of the left ventricle is the thickest.

Here, you can learn more about the heart and lungs.