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Circulatory System

The circulatory system travels through the entire body. Its important for supplying our muscles and organs with oxygen and nutrients, while assisting in the removal of waste, such as carbon dioxide.

Blood is a specialised fluid. It is made up of 4 main parts:

In this closed system the pipes are called Arteries, capillaries and veins.

Arteries carry blood away from the heart to the body. They are very thick since they are under a lot of pressure.

Veins carry the blood from the body to the heart, and since they are carrying the blood back the pressure is a lot less. This means they aren’t as thick as Arteries.

Capillaries are tiny. In fact they are so small that red blood cells have to go single file through them. This is where the majority of diffusion occurs

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The pump. When the heart stops, its game over. Without the heart constantly pumping, there is no way your muscles or organs can get oxygen.

The heart is a very special organ. Its not made our of normal muscular tissue like your legs or arms, but out of a special muscle tissue called cardiac muscle.

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The circulatory system is essentially a closed series of pipes throughout the body.

Every pipe system requires some sort of pump to keep the fluid moving.

So first lets start with the pipes.

Year 9 iGCSE - Biology