Human Defences (P1)

Question 1

Antigens

Answer 1

Proteins on the surface of all cells and pathogens

Question 2

Anti-toxins

Answer 2

Neutralise toxins produced by bacteria

Question 3

Anti-bodies

Answer 3

Bind to antigens on pathogens. Either cause direct damage or stick pathogens together

Question 4

Process of defence

Answer 4

1. A pathogen gets inside your body and begins to multiply
2. Phagocytes engulf and digest the pathogen
3. B-cells start to produce anti-bodies and anti-toxins
4. Anti-bodies stick to proteins on the surface of the pathogen
5. Anti-bodies can punch holes in the pathogen and kill it
6. After a couple of days there will be enough of the pathogen to make you ill

Question 5

Runny eyes/nose
Coughing/sneezing
Reddening of tissues

Answer 5

Runny eyes/nose wash out the pathogen leaving less to multiply, the eyes’ fluid is antimicrobial
Coughing and sneezing removes any remnants from the throat
Reddening if tissues allows white blood cells to go to the disease

Question 6

Mucus
Antimicrobial fluids
Cilia

Answer 6

Mucus provides a layer which takes up space on the outside of bodily tracts
Antimicrobial fluids break down the bacteria and wash them out
Cilia provides a lining to stop other diseases passing

Question 7

Skin
Bacteria
Stomach acid

Answer 7

The skin provides a defensive barrier against diseases
Bacteria takes up space to stop other bacterium
Stomach acid destroys bacteria in the stomach

Question 8

Phagocytosis

Answer 8

Where a cell binds to or engulfs something

Question 9

Lymphocytes

Answer 9

Detect antigens and produce the relevant antibodies

Question 10

Coronary heart disease

Answer 10

Where the coronary arteries are blocked by a build up of fatty material around the outside

Question 11

Phagocytes

Answer 11

Engulf and destroy pathogens