1.5 - Defence mechanisms

Question 1

What defence mechanisms are there to prevent pathogens from entering the body?

Answer 1

1) The skin prevents pathogens entering the body

2) Mucus traps the pathogens, which are then killed by stomach acid

Question 2

Once pathogens are in the body, how does the body defend itself?

Answer 2

With white blood cells, which are part of the immune system

Question 3

In what three ways do white blood cells defend the body?

Answer 3

1) Phagocytes ingest the pathogens (phagocytosis)
2) Lymphocytes produce antibodies that attach to the pathogen’s antigens
3) Lymphocytes produce antitoxins to counteract the toxins produced by pathogens