THE HEART AND ITS ROLE IN THE CIRCULATORY SYSTEM

THE HEART AND CIRCULATORY SYSTEM

All must be able to identify the organs in the circulatory system. Draw and labelling the heart (Level 3)

Most should be able to describe the heart and the main blood vessels and their role. Finding there pulse! (Level 4-5)

Some could describe the role of the ‘double pump.’ (Level 6)

Learning objectives:

569 × 477 - en.wikipedia.org

Oxygenated blood -

•Blood that contains oxygen •Mainly found in arteries

Deoxygenated blood -

•Blood that does not contain oxygen•Mainly found in veins

ARTERIES Carry blood away from the heart.The blood in the arteries is under high pressure and so:•Arteries have thick outer walls•Arteries have thick layers of muscles and elastic fibres

VEINSCarry blood to the heart.The blood in the veins is under low pressure and so:• Veins have thin walls•Veins have thin layers of muscle and elastic fibres

In the organs, blood flows in capillaries

Unlike arteries, veins have one-way valves in them to keep the blood moving in the correct direction.

http://www.bbc.co.uk/schools/gcsebitesize/science/21c/disease/heartdiseaserev2.shtml

The heart is a DOUBLE PUMP:

1st - blood is pumped to the lungs & returns to the heart,2nd - blood is pumped to respiring muscles & back to the heart again.

1. Deoxygenated blood is pumped from the heart to the lungs

2. The blood receives oxygen and is pumped back to the heart

4. The oxygen leaves the blood to be used for respiration in the body and the blood goes back to the heart

3. The oxygenated blood is then pumped to the rest of the body

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THE HEART