The immune system
If a Microorganism that causes disease. does manage to enter the body, the The body's defence system against entry of any foreign body, including pathogens and agents such as pollen grains. The role of the immune system is to prevent disease. will attempt to destroy it.
White blood cells are an important part of the immune system.
White blood cells help to defend the body through:
- phagocytosis:
- Cells, such as white blood cells, that engulf and absorb waste material, harmful microorganisms, or other foreign bodies in the bloodstream and tissues. surround any pathogens in the blood and engulf them
- A protein which catalyses or speeds up a chemical reaction. in the phagocyte break down the pathogen and destroy it
Phagocyte engulfing a bacterial cell
- producing antibodies:
- A protein produced by the immune system in humans (and other animals) that attacks foreign organisms (antigens) that get into the body. attach to the foreign body, eg a Single-celled microorganisms, some of which are pathogenic in humans, animals and plants. Singular is bacterium. or An ultramicroscopic infectious non-cellular organism that can replicate inside the cells of living hosts, with negative consequences.
- the phagocyte is then able to recognise the bacterium or virus as being foreign, and not one of the body's cells
- antibodies also cause pathogens to stick together, making it easier for phagocytes to engulf them
- producing antitoxins:
- antitoxins neutralise the A type of natural poison produced by an organism, often as a form of protection. produced by pathogens
