B3: human defense system

Question 1

what are some first line defenses?

Answer 1

skin
nose
throat / mouth
stomach

Question 2

how is the skin a line of defense?

Answer 2

it is a physical barrier, it produces sebum and antimicrobial substances, which kill the pathogens

Question 3

how is the throat a line of defence

Answer 3

covered in mucus which trap particles and the cilia move mucus to the back of the throat so we can swallow it

Question 4

how is the nose a line of defence

Answer 4

it has lots of hairs and mucus which trap the pathogens

Question 5

what kind of acid does the stomach contain?

Answer 5

hydrochloric acid, and this kills the pathogenes

Question 6

what makes up the immune system?

Answer 6

white blood cells

Question 7

what are the three main funtions of white blood cells?

Answer 7

produce antitoxins
produce antibodiees
carry out phagocytosis

Question 8

when do WBCs produce antitoxins?

Answer 8

lymphocytes produce antitoxins to neutralise the toxins produced by the bacteria when there is a bacterial infection

Question 9

describe the process of producing antibodies

Answer 9

pathogens have antigens - markers - on the surface and the body recognisses these as foreign, and the lymphocytes produce COMPLEMENTARY protiens called antibodies, which bind to the antigen and signal to the white blood cells to destroy them.

Question 10

how is phagocytosis performed?

Answer 10

phagocytes can directly engulf the pathogen by tracking them down, binding to them and detroying them