Plasma

• Do not have a nucleus
• Contain haemoglobin
• Haemoglobin combines with oxygen to form oxyhaemoglobin
• Carry oxygen to all the organs where the oxyhaemoglobin splits into oxygen and haemoglobin

• Have a nucleus
• Form part of the body's defence system against microorganisms

• Do not have a nucleus
• Small fragments of cells
• Help blood to form clot at a wound

1) Fibrinogen changes into fibrin

2) Forms a network of fibres trapping the blood cells and forming a clot

3) Blood dries forming a scab