Defence against disease TOPIC 3

Question 1

What is the first line of defence

Answer 1

natural human defence systems

Question 2

What are specific defence systems

Answer 2

a defence against a certain type of pathogen due to its unique antigens

Question 3

Define non-specific defence system

Answer 3

a generalised defence against any pathogen

Question 4

is the first line of defence specific or non-specific

Answer 4

non-specific

Question 5

what are the natural human defence systems

Answer 5

• skin
• stomach
• nose
• trachea & bronchi
• tears

Question 6

how does the skin defend against pathogens

Answer 6

• acts as a physical barrier
• sebaceous glands produce oils to kill microbes

Question 7

what glands in the skin produce oil

Answer 7

sebaceous

Question 8

how does the stomach defend against pathogens

Answer 8

• contains hydrochloric acid whih kills swallowed micorbes

Question 9

how does the nose defend against pathogens

Answer 9

• nasal hairs act as a physical barrier
• sticky mucus trabs dust and microbes

Question 10

how does the trachea and bronchi defend against pathogens

Answer 10

• goblet cells produce mucus
• ciliated cells propel mucus back up the air way

Question 11

what happens to the mucus once it has been propelled by the ciliated cells

Answer 11

you either cough the mucus up or swallow it and it gets digested naturally

Question 12

how do tears defend against pathogens

Answer 12

• they contain ensymes called lysozymes which destroy microbs, preventing them entering the eye

Question 13

what are the enzymes in tears

Answer 13

lysozymes

Question 14

what is the second line of defence

Answer 14

the bodys immune system ~ phagocytosis

Question 15

what are the 3 types of white blood cells

Answer 15

• phagocytes
• B-Lymphocyte
• T-Lymphocyte

Question 16

where do you find white blood cells

Answer 16

• circulating around the body in plasma
• static in some organs

Question 17

is phagocytosis specific or non-specific

Answer 17

non-specific

Question 18

what causes pathogens to clump together in pathocytosis

Answer 18

antibodies

Question 19

why is it good that pathogens clump together in pathocytosis

Answer 19

becuase it makes the process quicker

Question 20

what happens in phagocytosis

Answer 20

• antibodies cause pathogens to clump
• pathocyte engulfs pathogens into a vacuole
• digestive enzymes are added to break down pathogens

Question 21

what is the bodies 3rd line of defence

Answer 21

lymphocytes

Question 22

what do B-lymphocytes produce

Answer 22

antibodies

Question 23

what do T-lymphocytes produce

Answer 23

antitoxins

Question 24

are lymphocytes specific or non-specific

Answer 24

specific

Question 25

why are lymphocytes specific

Answer 25

because each antibody/toxin has to be complementry to the antigens on the surface of the pathogen

Question 26

how many different types of anitbody/toxin do lymphocytes produce

Answer 26

only one

Question 27

what do antitoxins do to toxins

Answer 27

they counteract them ~ neutralising them

Question 28

how do you make a monoclonal antibody

Answer 28

- mouse injected with specific antigen - B-lymphocytes produce anitbodies, then extracted - antibodies fused with tumour cell - forms hybridoma cell which is cloned - anibodies colleced and purified

Question 29

what is the name of a tumour cell fused with a anigbody

Answer 29

hybridoma

Question 30

why is a control window good in a pregnancy test

Answer 30

will show that the test has worked

Question 31

how does vacination work, what does it intorduce

Answer 31

- dead or inactive forms of a pathogen into the body - stimulates the white blood calls to rpoduce antibodies

Question 32

what are the pros and cons of vacines

Answer 32

+ helped reduce numbers of communicable diseases + prevents large outbreaks because many are vaccinated -dont always work -some suffer side effects, although rare

Question 33

how do antibiotics work

Answer 33

they kill infected bacteria inside the body

Question 34

why is it important for anitbiotics to be specific

Answer 34

because different antibiotics kill different types of bacteria

Question 35

do antibiotics work against viruses, why

Answer 35

no because viruses live inside host cells and are therefore out of reach of the anitbiotics

Question 36

why is it difficult to kill viruses medically

Answer 36

because it is hard to do it without damaging the body's tissues

Question 37

what do painkillers do

Answer 37

they treat the symptoms of a disease byt do not kill the pathogens causing it

Question 38

why are new drugs tested and trialed

Answer 38

to check they are safe and effective

Question 39

what are new drugs tested for

Answer 39

- toxicity ~ if they cause harm - efficacy ~ how well they work - dose ~ how much needs to be taken for best results

Question 40

what happens in the clinical trial

Answer 40

- given to healthy individuals in very low doses

Question 41

why are placebos used in drug trialing

Answer 41

to ensure valid and reliable data is collected with no bias

Question 42

what are the three stages of drug testing

Answer 42

- on human tissues and cells ~ cheap, doesnt tell much - on live animals ~ find efficacy & toxicty - clinical testing ~ healthy volunteers, dose increased

Question 43

what are monoclonal antibodies

Answer 43

identical copies of antibodies that have been made in labs

Question 44

what are the pros and cons of moloclonal antibodies

Answer 44

+ target any molecule + dont kill adjacent cells + produced in huge quantities + many uses -can create more side effects -not as widely used as hoped

Question 45

how does a preganancy test work

Answer 45

- dipstick is dipped into urine - it contains monoclonal antibodies, specific for a hormone in pregnant women, with blye dye paticle attached - the hormone binds to the complementary monoclonal anitbodies - the first widndow shows the result, where blue dye molecules will accumalate if positive - the control window shows the strip is working

Question 46

what is the hormone present in womens urine which indicates they are pregnant

Answer 46

hCG

Question 47

what time and why this time are women advised to use a pregnancy test

Answer 47

- after they first wake up - the concentration of hCG is higher and the test will be more reliable

Question 48

how are monolconal antibodies used to diagnse prostate cancer

Answer 48

- blood test for PSA uses monoclonal anitbodies - antibodies bind to PSA - washed to remove unbound antigens - anitbody with enzyme added & only binds if PSA present - well washed again - colourless substrate for enzyme added - enzyme converts to coloured product so PSA present