Defence against disease Flashcards

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1
Q

What is the first line of defence

A

natural human defence systems

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2
Q

What are specific defence systems

A

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

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3
Q

Define non-specific defence system

A

a generalised defence against any pathogen

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4
Q

is the first line of defence specific or non-specific

A

non-specific

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5
Q

what are the natural human defence systems

A
  • skin
  • stomach
  • nose
  • trachea & bronchi
  • tears
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6
Q

how does the skin defend against pathogens

A
  • acts as a physical barrier
  • sebaceous glands produce oils to kill microbes
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7
Q

what glands in the skin produce oil

A

sebaceous

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8
Q

how does the stomach defend against pathogens

A
  • contains hydrochloric acid whih kills swallowed micorbes
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9
Q

how does the nose defend against pathogens

A
  • nasal hairs act as a physical barrier
  • sticky mucus trabs dust and microbes
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10
Q

how does the trachea and bronchi defend against pathogens

A
  • goblet cells produce mucus
  • ciliated cells propel mucus back up the air way
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11
Q

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

A

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

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12
Q

how do tears defend against pathogens

A
  • they contain ensymes called lysozymes which destroy microbs, preventing them entering the eye
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13
Q

what are the enzymes in tears

A

lysozymes

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14
Q

what is the second line of defence

A

the bodys immune system ~ phagocytosis

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15
Q

what are the 3 types of white blood cells

A
  • phagocytes
  • B-Lymphocyte
  • T-Lymphocyte
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16
Q

where do you find white blood cells

A
  • circulating around the body in plasma
  • static in some organs
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17
Q

is phagocytosis specific or non-specific

A

non-specific

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18
Q

what causes pathogens to clump together in pathocytosis

A

antibodies

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19
Q

why is it good that pathogens clump together in pathocytosis

A

becuase it makes the process quicker

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20
Q

what happens in phagocytosis

A
  • antibodies cause pathogens to clump
  • pathocyte engulfs pathogens into a vacuole
  • digestive enzymes are added to break down pathogens
21
Q

what is the bodies 3rd line of defence

A

lymphocytes

22
Q

what do B-lymphocytes produce

A

antibodies

23
Q

what do T-lymphocytes produce

A

antitoxins

24
Q

are lymphocytes specific or non-specific

A

specific

25
Q

why are lymphocytes specific

A

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

26
Q

how many different types of anitbody/toxin do lymphocytes produce

A

only one

27
Q

what do antitoxins do to toxins

A

they counteract them ~ neutralising them

28
Q

how do you make a monoclonal antibody

A
  • 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
29
Q

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

A

hybridoma

30
Q

why is a control window good in a pregnancy test

A

will show that the test has worked

31
Q

how does a pregnancy test work

A
  • monoclonal anitbodies in the strip have a blue latex bead on them
  • if she is pregnant the hormone will bond to the monoclonal antibodies
  • then the monoclonal antibodies will stop at the test window showing a positive
32
Q

how does vacination work, what does it intorduce

A
  • dead or inactive forms of a pathogen into the body
  • stimulates the white blood calls to rpoduce antibodies
33
Q

what are the pros and cons of vacines

A

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

34
Q

how do antibiotics work

A

they kill infected bacteria inside the body

35
Q

why is it important for anitbiotics to be specific

A

because different antibiotics kill different types of bacteria

36
Q

do antibiotics work against viruses, why

A

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

37
Q

why is it difficult to kill viruses medically

A

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

38
Q

what do painkillers do

A

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

39
Q

why are new drugs tested and trialed

A

to check they are safe and effective

40
Q

what are new drugs tested for

A
  • toxicity ~ if they cause harm
  • efficacy ~ how well they work
  • dose ~ how much needs to be taken for best results
41
Q

what happens in the clinical trial

A
  • given to healthy individuals in very low doses
42
Q

why are placebos used in drug trialing

A

to ensure valid and reliable data is collected with no bias

43
Q

what are the three stages of drug testing

A
  • on human tissues and cells ~ cheap, doesnt tell much
  • on live animals ~ find efficacy & toxicty
  • clinical testing ~ healthy volunteers, dose increased
44
Q

what are monoclonal antibodies

A

identical copies of antibodies that have been made in labs

45
Q

what are the pros and cons of moloclonal antibodies

A

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

46
Q

how does a preganancy test work

A
  • 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
47
Q

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

A

hCG

48
Q

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

A
  • after they first wake up
  • the concentration of hCG is higher and the test will be more reliable
49
Q

how are monolconal antibodies used to diagnse prostate cancer

A
  • 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