Circulatory System
The circulatory system has a number of functions. These include…
- Carrying oxygen (from the respiratory system) and nutrients (from the digestive system) to cells
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- Carrying carbon dioxide (a toxic waste) from cells to the lungs (to be exhaled).
- Transports other wastes (e.g. urea) to where they can be excreted (excretory system).
- Distributes heat around the body (heat is a by-product of respiration).
Blood Vessels
 Arteries take blood away from the heart. |  Capillaries join the arteries and veins to body cells. |
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 Veins take blood to the heart. |
Your heart is about the size of your fist and made from a special type of muscle called cardiac muscle.
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The circulatory system is referred to as a double system because there are two separate circuits through which blood flows.
Circuit 1:
Blood travels from the heart to the body (except the lungs) and from the body back to the heart. This circuit is so nutrients (e.g. glucose) and oxygen can get to cells for respiration and CO2 and waste can be taken away from cells.
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Circuit 2:
Deoxygenated blood travels from the heart to the lungs, where it picks up oxygen and drops off carbon dioxide. The oxygenated blood then travels back to the heart.
Did you know.....
Veins appear blue due to the refraction of light through the skin.
Blood Components
Blood is made up of 4 key components…
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Red Blood Cells
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White Blood Cells
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Plasma
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Platelets
