Non-Specific Defences

Question 1

Define the term pathogen

Answer 1

A pathogen is a bacterium, virus or
other organism that can cause disease

Question 2

State the type of human cell that can
form a physical barrier to pathogens

Answer 2

Epithelial

Question 3

State the locations of epithelial
cells in the body

Answer 3

Skin and inner linings of the digestive
and respiratory tracts

Question 4

State the function of chemical
secretions such as tears, saliva,
mucus and stomach acid

Answer 4

To protect the body against invading
pathogens

Question 5

When are mast cells activated

Answer 5

In response to infection

Question 6

Name the chemical produced by
mast cells

Answer 6

Histamine

Question 7

State two effects of
histamine

Answer 7

Vasodilation

increased capillary permeability

Question 8

Explain how increased blood flow
during an inflammatory response can
help fight an infection

Answer 8

The increased blood flow leads to an accumulation of phagocytes and clotting elements at the site of infection

Question 9

What are phagocytes?

Answer 9

A type of white blood cell within the body, capable of engulfing and absorbing bacteria and other small cells and
particles.

Question 10

Name the process in which phagocytes recognise pathogens and destroy them

Answer 10

Phagocytosis

Question 11

Describe the process of
phagocytosis

Answer 11

The engulfing of pathogens and their
destruction by digestive enzymes
contained within lysosomes

Question 12

Name the proteins released by
phagocytes which attract more
phagocytes to the site of
infection

Answer 12

Cytokines

Question 13

State the function of cytokines

Answer 13

attract more phagocytes to thesite of infection

act as a signal to specific white blood cells causing them to accumulate at the site of infection