6.3 DEFENCE AGAINST INFECTIOUS DISEASE

Question 1

method of transmission of pathogens

Answer 1

Inhaled droplets
Direct contact
Bodily fluids
Animal vectors
Ingested/swallowed

Question 2

Innate immune system

Answer 2

Non-specific response to pathogens; doesn’t distinguish one pathogen from another; attempts to block
and stop them all.

Rapid response to pathogens

Is present before any exposure to pathogens. Is effective from the time of birth.

Short duration of response; immune response lasts for hours to a few days.

No immune memory is established;

Question 3

First line of defence (skin)

Answer 3

Skin
1. Protects external structures when intact
2. Not specific
3. Composed of predominantly dead skin cells
4. Contains biochemical defence agents
5. Secretes lactic acid and fatty acids to lower the pH

Question 4

first line of defence (skin)

Answer 4

Mucous membranes
1. Protects internal structures
2. Thin region of living surface cells that release fluids to wash away pathogens (mucus, saliva, tears…)
3. Contains biochemical defence agents
4. Membranes may be ciliated to aid the removal of pathogens