The Heart
Function
The heart pumps blood around your body. We have already learnt that blood carries important molecules like Oxygen, Carbon dioxide and Nutrients. The heart makes sure that these substances are transported as efficiently as possible. It is called a double pump because it pumps to the lungs and to the body at the same time. The structure of the heart helps it to do this and continue to do this the whole time you are alive.
Structure
The heart has 4 chambers called the left and right atrium and the left and right ventricle Atria are the two chambers at the top and the ventricles are the two chambers at the bottom.
In diagrams the heart may be shown as half blue and half red. This is to show the difference in where de-oxygenated blood and oxygenated blood flow through the heart.
Right side of the heart
Blood enters the heart through thew vena cava, emptying deoxygenated blood from the body into the right atrium of the heart.
As the atrium contracts, blood flows from your right atrium into your right ventricle through the open valve.
When the ventricle is full, the tricuspid valve shuts. This prevents blood from flowing backward into the atria while the ventricle contracts.
As the ventricle contracts, blood leaves the heart through the valve, into the pulmonary artery and to the lungs where it is oxygenated. Deoxygenated blood goes through the pulmonary artery to the lungs where CO2 is exchanged for O2.
Left side of the heart ( at the same time as the right side of the heart)
The pulmonary vein empties oxygenated blood from the lungs into the left atrium of the heart.
As the atrium contracts, blood flows from your left atrium into your left ventricle through the open mitral valve.
When the ventricle is full, the mitral valve shuts. This prevents blood from flowing backward into the atrium while the ventricle contracts.
As the ventricle contracts, oxygenated blood leaves the heart through the aortic valve, into the aorta and to the arteries and eventually into veins to complete the blood circulation in your body.
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