Blood is made up of four parts – plasma, red cells, white cells and platelets. Each part has a special job.
Plasma is a yellow liquid. It helps give you energy and grow.
Red blood cells carry oxygen to your cells.
White blood cells clean the blood and fight germs. When a virus enters your body, white blood cells rush to destroy the virus so you get better.
Blood carries oxygen and chemicals around the body, and takes waste products to the organs in the body that get rid of them.
It carries heat around our bodies, to keep our fingers warm and stop our brains from overheating.
It helps us fight infections and keep our body healthy.
The more oxygen there is in your blood, the brighter red it looks. The blood in your veins has less oxygen in it, so it looks much darker.
Blood makes up around 7% of the weight of a human body.
Lots of people give blood regularly. It’s important that enough blood is available for transfusions when people are badly hurt or unwell.
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