Biology B6 (16)

human immune system

defence system

skin acts as a barrier to pathogens it also secretes anitimicrobial substances which kill pathogens 

the whole respiratory tract is lined with cilia and mucus and there are hairs in the nose. the mucus and the hairs trap particles that could containpathogens and the cilia waft the mucus up to the back of the throat where it can be swallowed. 

eyes produce in tears an enzyme called lysoenzyme which break down bacteria on the surface of the eye 

the stomach produces hydrochloric acid this kills pathogens tht make it that far from the mouth

whne you damage a blood vessel, platelets in the blood clump togetehr to plug the damaged area. this is known as blood clotting blood clots stop you losing too much blood and prevent microorganisms rom entering the wound

you immune system can atttackpathogens

if a pthogen does enter your body…