Defence mechanisms

Question 1

In effect, what is an infection?

Answer 1

An interaction between the pathogen and the body’s various defence mechanisms

Question 2

How does one become immune? (general)

Answer 2

1) experience an infection and overwhelm the pathogen
2) the next time the pathogen infects the body’s defences are better and quicker and can therefore overwhelm the pathogen before harm is caused.

Question 3

What two forms of longer-lasting immunity are there?

Answer 3

1) cell-mediated responses involving T lymphocytes

2) humoral responses involving b lymphocytes

Question 4

What are the four different types of cell that are recognised as non-self?

Answer 4

• pathogens
• non-self material from organisms of the same species
• toxins
• abnormal body cells such as cancer cells

Question 5

Do specific lymphocytes exist prior to infections or are they produced in response?

Answer 5

Prior. these lymphocytes are complementary to the antigens on the surface of a non self cell.

Question 6

What are non specific defence mechanisms?

Answer 6

responses that are immediate and are the same for all pathogens.
These include: physical barriers such as the skin, tears, ear wax and acidic conditions and the process of phagocytosis.

Question 7

how are non self cells recognised?

Answer 7

The immune system can identify them by their specific proteins on their surface.