Preventing and Treating Disease

Question 1

Name 3 non-specific defences of the human body against all pathogens:

Answer 1

Skin, nose, stomach

Question 2

Name 2 ways the skin is a defence mechanism against pathogens.

Answer 2

1. Physical barrier to infection
2. Produces antimicrobial secretions
3. Microorganisms on skin prevent pathogens from growing

Question 3

Name a way the nose is a defence mechanism against pathogens.

Answer 3

1. Cilia and mucus trap particles in air, preventing them from entering lungs
2. Trachea and bronchi produce mucus

Question 4

Name a ways the stomach is a defence mechanism against pathogens.

Answer 4

Produces an acid that destroys pathogens in food, mucus and drinks

Question 5

What is the function of white blood cells?

Answer 5

To fight pathogens

Question 6

What are the two main types of white blood cells?

Answer 6

Lymphocyte, phagocyte

Question 7

What 2 ways do lymphocytes fight against pathogens?

Answer 7

1. Antitoxins
2. Antibodies

Question 8

How do antitoxins defend against pathogens?

Answer 8

Lymphocytes produce antitoxins - bind to the toxins produced by pathogens -> neutralises them

Question 9

How do antibodies defend against pathogens?

Answer 9

Lymphocytes produce antibodies that target pathogens -> they bind to antigens (proteins) on the pathogen’s surface.

Question 10

How do phagocytes defend against pathogens?

Answer 10

1. Phagocytes attracted to area of infection
2. Phagocytes surround and engulf pathogen
3. Enzymes are secreted -> digest and destroy the pathogen

Question 12

What does herd immunity mean?

Answer 12

Vaccinating a large proportion of the population against a disease -> makes it less likely to spread.

Question 13

What do antibiotics do?

Answer 13

Kill bacteria in the body.

Question 14

What does the specificity of antibiotics mean?

Answer 14

Specific bacteria need to be treated with specific antibiotics.

Question 15

What is the problem with antibiotics?

Answer 15

Some bacteria are becoming resistant to bacteria.

Question 16

What is the problem with drugs that kill viruses?

Answer 16

They often damage the body’s tissues.

Question 17

What can we use to treat viral diseases?

Answer 17

Painkillers - reduces pain but does not kill pathogens

Question 18

Where does digitalis come from?

Answer 18

Foxglove

Question 19

Where does aspirin come from?

Answer 19

Willow trees

Question 20

Where does penicillin come from?

Answer 20

Penicillium mould

Question 21

What 3 things are drugs trialed for?

Answer 21

1. Toxicity
2. Efficace
3. Dose

Question 22

What is the first step of clinical trials?

Answer 22

Pre-clinical trials

Question 23

What happens in pre-clinical trials?

Answer 23

Drug is tested in cells, tissues and live animals.

Question 24

What is the second step of clinical trials?

Answer 24

Clinical trials with volunteers

Question 25

What happens in clinical trials? (second step - with volunteers)

Answer 25

1. Healthy volunteers receive a *very low dose* to test efficacy and safety 2. If it is safe, more healthy volunteers receive the drug to find optimum dosage

Question 26

What is the third step of clinical trials?

Answer 26

Peer review

Question 27

What happens during peer review (clinical trials)?

Answer 27

The results of clinical trials are tested and checked by researchers

Question 28

What is the fourth step of clinical trials?

Answer 28

Double-blind trials

Question 29

What happens in double-blind trials?

Answer 29

Patients are given a *placebo* drug. Double-blind - neither the patients or the doctors know who has been given the real drug or the placebo.

Question 30

What happens in vaccination?

Answer 30

1. *Small quantities of dead or inactive pathogens* are injected into the body. 2. Stimulates lymphocytes to *produce correct antibodies* for the pathogen. 3. If the same pathogen re-enters the body, the correct *antibodies can be produced quickly* to prevent infection,

Question 31

Why does the concentration of antibodies produced increase upon infection (after vaccination)?

Answer 31

Lymphocytes have already produced antibodies -> they can now produce them *quicker and at a higher concentration* to prevent an infection