1. The Circulatory System

2. Your blood works non-stop, 24 hours day.
It carries carbon dioxide and other waste away.
Blood is pumped round the body by the ‘HEART’.
It flows along tubes called ‘BLOOD VESSELS’.
The blood, heart and blood vessels together make up your ‘CIRCULATORY SYSTEM’.

3. How Blood is carried around the body
Every time your heart beats it pumps blood at high pressure around your body in tubes in the following order:
Arteries (Thick and elastic)
Arterioles
Cappillaries (1 cell thick so that blood transfusion can take place)
Venules (deoxygenated blood)
Veins

4. The valves in veins
Blood in veins travels very slowly as it has lower pressure.
They have ‘one way’ valves.
Most large veins are in your arms and legs.
When the muscles contract, they squirt the blood towards your heart.

5. REMEMBER
Arteries always carry oxygenated (with O2) blood away from the heart.
AND
Veins always carry deoxygenated (without O2) blood to the heart.