Practice Questions
1.How much blood is in the human body?
4.7 to 5 litres
2. Fill in the table below to summarise function of each component of blood.
| Component of blood | Function |
|---|---|
| Plasma | Transport substances |
| Red blood cells | Transport oxygen |
| White blood cells | Form part of the immune system |
| Platelets | Used for blood clotting |
3. Explain how white blood cells form part of our immune system.
Phagocytes engulf pathogens and use digestive enzymes to break down the pathogen
Lymphocytes produce antibodies to bind to antigens on pathogens, to kill the pathogens. Lymphocytes will also produce antitoxins which neutralise toxins produced by bacteria.