Infection and response - Fighting disease

Question 1

how does the skin defend against pathogens

Answer 1

• has antimicrobial substances which kill bacteria
• outer layer of skin consists of dead cells which makes it difficult for pathogens to penetrate

Question 2

how does mucus in the nose defend against pathogens

Answer 2

the hair in your nose traps particles that could contain pathogens

Question 3

how do the trachea and bronchi defend against pathogens

Answer 3

• they secrete mucus to trap pathogens
• they are lined with cilia which are hair - like structures which waft the mucus up the back of the throat where it can be swallowed

Question 4

how does the stomach defend against pathogens

Answer 4

• contains hydrochloric acid which kills pathogens that make it that far from the mouth

Question 5

how does your immune system attack pathogens

Answer 5

by using white blood cells to consume them and produce antibodies

Question 6

what is phagocytosis

Answer 6

when white blood cells engulf foreign cells and digest them

Question 7

how does the immune system react to bacteria producing toxins to damage tissues (antitoxins)

Answer 7

The immune system responds to this by producing antitoxins, which neutralise the toxins released by the bacteria and prevent them from causing harm.

Question 8

what are antibodies and how do they prevent disease

Answer 8

protein molecules that are produced when a foreign antigen comes in contact with a white blood cell
Antibodies are specific to particular pathogens
- produced rapidly around the body to find similar virus or bacteria to kill it

Question 9

how do vaccines work step by step

Answer 9

1. dead or inactive pathogen injected into the body
2. these carry antigens which cause your body to produce antibodies to attack them even though the pathogen is harmless
3. At the same time, the white blood cell divides by mitosis to produce lots of copies of itself
   - these copies of the white blood cell can stay in the blood for decades and theyre called memory cells
4. If your body comes into contact with the live version of the pathogen , the white blood cells can rapidly produce the correct antibodies to kill off the pathogen and prevent infection

Question 10

pros of vaccines

Answer 10

stops big outbreaks of disease
controls the spread of disease, herd immunity

Question 11

cons of vaccines

Answer 11

• sometimes they don’t work, sometimes you don’t get immunity
• someone could have a bad reaction to the vaccine, these are rare

Question 12

what are antigens

Answer 12

proteins found on the surface of cells

Question 13

what is herd immunity

Answer 13

immunising a large proportion of the population will make it very hard for a pathogen to be spread. This is called herd immunity.

Question 14

what kind of shape do antibodies have and why

Answer 14

Antibodies have a complementary shape to the antigen on the surface of the pathogen and lock onto them, effectively ‘tagging’ them

Question 15

what are painkillers

Answer 15

drugs that reduce symptoms but don’t kill pathogens- e.g - aspirin

Question 16

what are antibiotics

Answer 16

drugs that kill or prevent the growth of the bacteria causing the problem without killing your body cells
- they have greatly reduced the amount of deaths from communicable diseases

Question 17

cons of antibiotics

Answer 17

• don’t destroy viral pathogens
• some bacteria can mutate and become resistant to the antibiotics ( MRSA ) meaning the antibiotic will only kill the non - resistant strain and the resistant one will reproduce
• this can happen if someone takes the wrong antibiotic or doesn’t take it for the full length that they are told to

Question 18

how do some antibiotics work

Answer 18

by destroying the cell wall of bacteria so they can’t replicate

Question 19

what are the 3 main stages of drug testing

Answer 19

• preclinical testing on human cells and tissues in a lab
• preclinical testing on live animals
• clinical testing on human volunteers in a clinical trial

Question 20

what plant did aspirin originate from

Answer 20

willow

Question 21

what plant did digitalis originate from

Answer 21

foxgloves

Question 22

what drugs are used to treat viral infections

Answer 22

antiviral

Question 23

what questions need to be asked when testing a drug

Answer 23

• is the drug safe? Toxicity
• does the drug work? Efficacy
• how much of the drug is needed? Dose

Question 24

summarise preclinical testing

Answer 24

done in a laboratory using cells, tissues and live animals.

Testing on animals is useful for working out how toxic (harmful) a drug is to cells.
In the UK, new medicines have to undergo tests on two different live mammals.

Question 25

summarise clinical testing

Answer 25

if the drug passes preclinical testing, the drug is tested on healthy volunteers to make sure it is safe

• the patients are randomly put into two groups, one is given the new drug, one is given the placebo, this is so that the doctor can see the actual difference the drug makes
• clinical trials are double blind, the patients do not know if they got the real or placebo, the doctor doesnt know either

Question 26

why must the results of drug testing be assessed by peer reviews

Answer 26

to prevent false claims

Question 27

What term is used to describe whether a drug works or not

Answer 27

efficacy

Question 28

how do antiretroviral drugs help someone with HIV

Answer 28

They stop the virus replicating in the persons body

Question 29

how can we slow down the rate of antibiotic resistant strains developing

Answer 29

• doctors should avoid over prescribing antibiotics, so you should only get them for something serious
• dont prescribe for viruses
• make sure to finish the whole course of antibiotics, don’t just stop when you feel better

Question 30

what is the function of the immune system

Answer 30

to destroy pathogens and any toxins they produce

• to protect us in case the same type of pathogen invades us again in the future

Question 31

how do wbcs prevent disease

Answer 31

• phagocytosis
• releasing antibodies
• releasing anttoxins to neutralise toxins released by bacteria

Question 32

what was the first painkiller

Answer 32

penicillin

Question 33

what is antibiotics resistance

Answer 33

when bacteria has evolved to a point where they can no longer be killed by a certain antibiotic

Question 34

why would it be difficult to develop drugs that kill viruses

Answer 34

because viruses live and reproduce INSIDE human cells, so it would be difficult to develop drugs that kill viruses without damaging the bodys tissue

Question 35

Why are placebos used in a double blind trial?

Answer 35

To prevent bias

Question 36

what does mmr stand for

Answer 36

measles mumps rubella

Question 37

what is thalidomide used to treat

Answer 37

leprosy

Question 38

why do legal non prescribed drugs have a greater impact on the health of the population than illegal drugs

Answer 38

• because they are more readily available
• more people use them

Question 39

why is it difficult for a person to stop taking certain drugs

Answer 39

because of addiction or dependency