Body defences

Skin, and mucous membranes

• micro organisms that have adapted to living on the skin and other parts of the body and are present in areas like hair follicles and pores. • Don’t usually cause disease • prevent other microorganisms from growing out of control on the skin surface.

• microorganisms that are picked up and put on other surfaces • more likely to cause infection or illness

Line cavities that communicate with outside such as gastrointestinal tract

• Tears, saliva, sweat and vaginal secretions contain lysozyme • stomach acid has a pH level of 2 making it very acidic so it can destroy most micro organisms • Lactoferrin is found in the saliva and breast milk, it inhibits the growth of some microorganisms

an antibacterial enzyme