5.1 Defence Mechanisms

Question 1

What are the two types of lymphocyte responses?

Answer 1

• cell-mediated response, involving T cells
• humoral responses, involving B cells

Question 2

The protein molecules found on cells allow the immune system to identify:

Answer 2

• pathogens, such as HIV
• non-self material, such as cells from same species
• toxins, including those produced by pathogens such as bacterium that cause cholera
• abnormal body cells, such as cancer

Question 3

What are the two types of defence mechanisms?

Answer 3

• specific (response slower and specific to each pathogen)
• non specific (response is immediate and the same for all pathogens)

Question 4

What are the two types of non-specific defence mechanisms?

Answer 4

• physical barriers e.g. skin
• phagocytosis

Question 5

What are the two types of specific defence mechanisms?

Answer 5

• cell-mediated response (T lymphocytes)
• humoral response (B lymphocytes)

Question 6

How do lymphocytes recognise cells belonging to the body?

Answer 6

• they collide with body cells when the foetus is in the womb and the receptors will fit those exact cells, these lymphocytes die and the rest that might fit foreign material remain

Question 7

How does inflammation work? (6 stages)

Answer 7

1) histamines are released, act as inflammatory mediators
2) swelling and redness formed
3) chemicals attract phagocytes white blood cells such as NEUTROPHILS and MACROPHAGES
4) phagocytosis starts
5) phagosome formed
6) phagolysosome formed, kills pathogen