Additional Applied Science - health, exercise and nutrition

Blood is made up of four things

Red blood cells - transport oxygen from the lungs to all the cells

White blood cells - to fight infection

Platelets - to help blood to clot at the site of a wound

Plasma liquid that carries everything about

Three types of blood vessels

Arteries - carry blood away from the heart

Capillaries - exchanging materials at the tissues

Veins - carries blood to the heart

Arteries

• Carries blood under pressure
• The walls are elastic and strong
• Press down on the artery lightly, you can feel the pulse every time the heart beats

Capillaries

• Really small
• carry blood close to every cell in the body
• supply oxygen and nutrients and take away waste like Co2
• Walls are thick
• Walls are permeable because the substances can move in and out

Veins

• Take blood back to the heart
• The blood is at low pressure
• There is a bigger lemen 
• They have valves to keep the blood flowing in the right direction

• Pumps blood around the body
• Right side of the heart pumps blood to the lungs
• Left side of the heart pumps blood to the rest of the body