Body defencesSpec 10.1.4
The body has defences that stop pathogens getting in, and others that destroy the ones that do get in.
| Defence | How it protects the body |
|---|---|
| Skin | Forms a tough barrier that stops pathogens entering the body. |
| Hairs in the nose | Trap dust and pathogens in the air that is breathed in. |
| Mucus | Sticky liquid in the nose and airways that traps pathogens so they can be removed. |
| Stomach acid | Kills most pathogens that are swallowed in food and drink. |
| White blood cells | Destroy pathogens that get inside the body, for example by ingesting them (phagocytes) or by making antibodies (lymphocytes). |
Common mistake:
Hairs and mucus do not kill pathogens. They trap them. Stomach acid and white blood cells are the defences that kill or destroy pathogens.