B6 Preventing And Treating Diseases

Question 1

What is the human defence system made out of

Answer 1

The general defence system

the specific defence system

Question 2

Where can pathogens into the body

Answer 2

Eyes, nose, mouth, cuts, ear and the penis or vagina

Question 3

Is the general defence system

Answer 3

Tries to stop pathogens entering the bloodstream

made up of the bodies natural barriers

they act against pathogens

Question 4

What are the general defence system barriers

Answer 4

Skin
stomach acid- hydrochloric acid
Mucus
earwax

Question 5

What is this specific defence system

Answer 5

If the general defence system fails the body relies on the specific defence system

Made up of white blood cells found in the blood

Question 6

What are the two types of white blood cells

Answer 6

Phagocytes

Lymphocytes:

Question 7

What does phagocytes do

Answer 7

engulf pathogens and digest them making them harmless

Question 8

What does Lymphocytes do

Answer 8

produce antibodies in response to ‘foreign’ antigens.

The antibodies attach to the antigens destroy them.

They also can produce antitoxins which cancel out the effect of the pathogen’s toxins.

Question 9

What are antigens

Answer 9

Every cell in our body has one

They are like ID cards meaning that the body can figure out if it is meant to be in your body or not

Question 10

What are memory lymphocytes

Answer 10

These are the cloned remains of the original lymphocyte

Which means that if that pathogen attacks again the body can produce antibodies quicker than the original time

Question 11

How does a vaccination provide immunity?

Answer 11

A dead/weakened/inactive pathogen is injected into the patient’s bloodstream. The pathogen still retains the antigens.

Specific lymphocyte recognises the specific antigens and 1) produces clones of itself and 2) produce large amounts of the correct antibody.

After the lymphocyte has destroyed the pathogen the antibodies are broken down, but the clone of lymphocytes remain in the bloodstream as ‘memory lymphocytes’.

This provides immunity to that specific pathogen.

If the same pathogen re-enters the body the white blood cells respond (more) quickly to produce large amounts of the correct antibodies, preventing infection.

Question 12

What is herd immunity

Answer 12

Vaccinating a large proportion of the population against a certain pathogen (e.g. flu vaccine).

This is to reduce the number of people getting the disease and avoid an outbreak.

Question 13

Where did traditional drugs come from

Answer 13

plants

microorganisms

Question 13

Where dod the heart drug digitalis originate

Answer 13

from foxgloves

Question 14

Where did the painkiller aspirin originate

Answer 14

from willow

Question 15

Where did Penicillin originate and who discovered it

Answer 15

from the Penicillium mould

discovered by Alexander Fleming

Question 16

Why are drugs Rigourously trialled and tested

Answer 16

So they are safe
So do not have any toxic side effects
So the correct dose is given
So they are stable – can be taken under normal conditions and can be stored safely.

Question 17

What are the different stages of Drug trials

Answer 17

Pre-clinical trials: this is where drugs are tested on cells, tissues and live animals e.g. mice. This is to ensure there are no unwanted side effects.

Clinical trials: this is where the drug is tested on humans. There are 3 stages.

Phase 1: drug is tested on healthy volunteers. Low doses are used.
Phase 2: drug is tested on people who actually have the disease (i.e. the patient).

Double blind trial: Some patients are given the actual drug, some are given a placebo (a ‘fake’ drug without the active ingredient). Neither the patient nor the doctor knows who has been given the drug or placebo. This is to remove bias. At the end of the trial the Scientists from the drug company can compare data.

Phase 3: larger numbers of patients are used. Patients are given the drug or placebo. This is to verify the efficacy/effectiveness of the drug and to determine the correct
dose.

Question 18

What are antibiotics?

Answer 18

Antibiotics are chemicals that kill (pathogenic) bacteria inside the body. Specific antibiotics kill specific bacteria.

Question 19

Why do antibiotics not kill viruses?

Answer 19

They do not work against viruses because viruses live and reproduce inside cells.

Question 20

Why is it difficult for Scientists to develop drugs that kill viruses?

Answer 20

It is difficult to develop drugs that kill viruses as viruses reproduce inside cells.

Therefore it is difficult to just kill the virus and not the body’s tissues too.

Question 21

How do bacteria become resistant to certain antibiotics?

Answer 21

1. Antibiotics kill individual bacterial pathogens of the non-resistant strain.
2. Resistant/mutated pathogens survive and reproduce.
3. The population of the resistant strain of pathogens increases because they are not
   affected/killed by the antibiotic.
4. The resistant strain will then spread because people are not immune to it and there is
   no effective treatment.

Question 22

How can we reduce the spread of antibiotic resistant bacteria?

Answer 22

Do not prescribe antibiotics for mild infections because they will get better due to the body’s normal immune system

Do not prescribe antibiotics for viral infections / colds / flu because antibiotics do not kill viruses

If you do prescribe antibiotics make sure the patient finishes the full course because
any bacteria left may develop resistance, survive and reproduce rapidly (due to lack
of competition)