IGCSE Biology / Blood and circulation

Phagocytes, antibodies and clotting

Edexcel International GCSE Biology (4BI1), chapter 5: Blood and circulation, specification point 2.62, 2.64B. Part of the full course.

Read the revision notes · IGCSE Biology past papers

Phagocytes and lymphocytes defend the body in different ways: phagocytes engulf pathogens, while lymphocytes make specific antibodies. Platelets and fibrin also seal damaged blood vessels, helping to prevent blood loss and keep pathogens out.

More lessons in Blood and circulation

• Why small organisms manage without a transport system and large ones cannot
• Double circulation
• The structure of the heart
• How the heart beats
• Coronary arteries and heart disease
• How heart rate changes during exercise and under adrenaline
• Adrenaline and the body's response
• Arteries, veins and capillaries
• Plasma, red cells, white cells and platelets
• Vaccination, memory cells and the secondary response