Ch.2b Protect Barriers And Immunity Against Disease

Question 1

Infected diseases caused by pathogens

Answer 1

1. Bacteria-> cholera 霍亂
2. Viruses -> AIDS
3. Fungi -> Hong Kong foot
4. Protozoans -> malaria 瘧疾

Question 2

Prions example

Answer 2

BSE -> mad cow disease

Question 3

First line of defense

Answer 3

Physical barriers and chemical barriers

Question 4

Second line of defense

Answer 4

Non specific immune response, e.g. Cell attack, interferon and inflammatory response

Question 5

Third line of defense

Answer 5

Immunity

Question 6

Examples of physical and chemical barriers

Answer 6

Physical barriers:

1. Skin
2. Cornea
3. Mucus layers
4. Outflow

Chemical barriers:

1. Stomach acid
2. Fatty acids on skin
3. Lysozyme in tears

Question 7

Mucous membranes

Answer 7

1. Linings of body openings ( e.g. Eyes) and tubes that open to the outside ( e.g. Digestive and respiratory tracts)
2. Mucous cells produces a sticky, viscous secretion called mucus

Question 8

Examples of active immunity

Answer 8

1. Natural active immunity
   - > acquired due to infection
2. Artificial active immunity
   - > vaccination
   e. g. Whole live microorganism, dead microorganism

Question 9

Example of passive immunity

Answer 9

Natural passive immunity
-> a mother ‘s antibodies pass across the placenta to the foetus and remain for several months

e.g. Colostrum ( the first breast milk) contains lots of IgA ( a type of antibodies) which remain on surface of the baby’s gut wall and pass into blood

Question 10

Why aren’t vaccination always effective?

Answer 10

1. Some people don’t respond well/ at all to vaccinations

2. Antigenic variation cases by mutation

Question 11

Active immunity VS passive immunity

Answer 11

Active immunity:
This is immunity where the body is actively producing antibodies to fight infection

Passive immunity:
This is immunity where antibodies are given to a person from the blood of another person or animal