Human defences (infections pt2)

Question 1

What the non-specific defence systems of the human body against pathogens? (5/6)

Answer 1

• skin
• nose
• trachea and bronchi
• stomach
• eyes

Question 2

what does non-specific defences against disease mean?

Answer 2

the first line of defence against pathogens in general

Question 3

How does the skin protect the body from diseases?

Answer 3

it acts as a barrier to pathogens and secretes antimicrobial substances which kill pathogens.

the sebaceous gland produces sebum which kills bacteria and fungi

Question 4

How does the nose protect the body from diseases?

Answer 4

the mucas and the hairs traps particles and bacteria

Question 5

How does the trachea and bronchi protect the body from diseases?

Answer 5

sheet of mucas traps particles and bacteria. Cilla waft the mucas up to the back of the throat where it can be swallowed

Question 6

How does the stomach protect the body from diseases?

Answer 6

glands and hydrochloric acid, kills bacteria in food

Question 7

How does the eyes protect the body from diseases?

Answer 7

enzymes in tears destroy micro-organisms

Question 8

How does white blood cels help defend against pathogens?

Answer 8

phagocytosis
antibody production
antitoxin production.

Question 9

What is phagocytosis

Answer 9

engulfying foreign cells and digesting them

Question 10

How does the white blood cells use antibodies to defend against pathogens?

Answer 10

• When white blood cells come across a foreign antigen they will start to produce antibodies to lock onto the invading cells so that they can be found and destroyed by other white blood cells
• Antibodies are produced rapidly and carried around the body to find all similar bacteria or viruses

Question 11

Why wont antibodies lock onto every antigen

Answer 11

because antibodies produced are specific to that of the antigen - they won’t lock onto any other

Question 12

What would happen if the person is infected with the same pathogen again?

Answer 12

the white blood cells will rapidly produce the antibodies to kill it - the person is naturally immune to that pathogen

Question 13

What are vaccintions?

Answer 13

introducing small quantities of dead or inactive forms of a pathogen into the body

Question 14

why do vaccinations have pathogens?

Answer 14

to stimulate the white blood cells to produce antibodies. .

this means if the same pathogen re-enters the body, the white blood cells respond quickly to produce the correct antibodies, preventing infection.

Question 15

What is herd immunity?

Answer 15

when a large proportion of the population are vaccinated so the pathogen won’t be spread easily

Question 16

What are the advantages of vaccinations?

Answer 16

• help control lots of communicable diseases that were once common in the UK
• Epidemics can be prevented if a large percentage of the population is vaccinated. this means people who aren’t vaccinated against the disease would be protected through herd immunity

Question 17

What would happen if a signifcant amount of people aren’t vaccinated against a communicable disease?

Answer 17

the diease can spread quickly through them and lots of people will be ill at the same time

Question 18

What are the disadvantages of vaccinations?

Answer 18

• Vaccines dont always work: sometimes they don’t give immunity
• You can have bad reaction to a vaccine . But these are rare

Question 19

What are examples of bad reactions to vaccinations

Answer 19

swelling or fever

Question 20

What do Antibiotics do?

Answer 20

Antibiotics, (e.g.penicillin) are medicines that help to cure bacterial disease by killing infective bacteria inside the body.

specific bacteria should be treated by specific antibiotics.

Question 21

Why is it difficult to destroy viruses?

Answer 21

because viruses reproduce using your body cells which makes it very difficult to develop drugs that destroy viruses without killing the body cells

Question 22

How has the use of antibiotics impacted society?

Answer 22

The use of antibiotics has greatly reduced deaths from infectious bacterial diseases.

However, the emergence of strains resistant to antibiotics is of great concern.

Question 23

How are resistant bacteria strains created?

Answer 23

bacteria mutations which can cause bacteria to be resistant to antibiotics

the resistant bacteria will survive and reproduce and the population of the resistant strain will increase (natural selection)

Question 24

What is an example of a bacteria strain that is resistant to antibiotics?

Answer 24

MRSA

causes serious wound infections and is resistant to the most powerful meticillin

Question 25

How can the rate at which resistant strains of bacteria develop be decreased?

Answer 25

by doctors avioding over-prescribing antibiotics

Question 26

why is it important for paitents to finish the whole course of antibiotics?

Answer 26

so that they are killed and none survive to form resistant strains

Question 27

What are the 2 main roles drugs can have?

Answer 27

• cure the problem

- relieve the symptoms

Question 28

What is the job of an anti-viral drug?

Answer 28

To kill the virus without also damaging the body’s tissues

Question 29

What is digitalis and where did it originate from?

Answer 29

• heart drug

- foxgloves

Question 30

What is aspirin and where did it originate from?

Answer 30

• painkiller

- willow

Question 31

who discovered Penicillin and where did it originate from?

Answer 31

• Alexander fleming

- penicillium

Question 32

Most new drugs are synthesised by ……

Answer 32

chemists in the pharmaceutical industry but the starting point may still be a chemical extracted from a plant

Question 33

New drugs are extensively tested for what three factors?

Answer 33

toxicity, efficacy and dose.

Question 34

What are the two main stages in testing drugs?

Answer 34

1) preclinical testing

2) clinical trials

Question 35

Where is preclinical testing done

Answer 35

in the laboratory using cells, tissues and live animals

Question 36

what are the substages in preclinical testing?

Answer 36

1) drugs are tested on human cells and tissues in the lab
* This allows efficacy and possible side effects to be tested

2) Drug is tested on live animals to see how the drug effects whole or multiple body systems
* allows testing for efficacy, toxicity and optimum dosage

Question 37

What happens in clinical trials?

Answer 37

• drug is tested on healthy volunteers to make sure it doesn’t have harmful side effects when the body is working normally
• dosage increases during the trial
• next the drug is tested on patients, the optimum dose is found (most effective with the least side effects)

Question 38

Double-blind trials are normally used to test patients.

What happens in a double-blind trial?

Answer 38

some patients are given a placebo, some are not.

• They are put randomly into 2 groups
• neither the doctor nor the patient knows who has what

Question 39

why are some patients in double-blind trials given placebos?

Answer 39

so the doctor can see the actual difference the drug makes - allows for the placebo effect

Question 40

why are doctors also “blind” during the double-blind trials?

Answer 40

so the doctors monitoring the patients and analysing the results aren’t subconsciously influenced by their knowledge

Question 41

Results of drug testing and drug trials aren’t published until they’ve neem through peer review. Why is this?

Answer 41

to prevent false claims