Session 3 - Innate Immmunity Flashcards

1
Q

define the immune system

A

cells and organs that contribute to immune defences against infectious and non-infectious conditions

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2
Q

true or false: cancer is a type of non-infectious condtion

A

true

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3
Q

define infectious disease

A

when a pathogen succeeds in evading and overwhelming the hosts immune defences

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4
Q

what physical barriers are involved in the innate immune system

A
  • skin
  • musocus membranes
  • bronchial cilia
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5
Q

what are the differences in the innate and adaptive immunity

A

Innate:

  • fast
  • lacks specificity
  • lacks memory
  • no change in intensity
  • first line of defence
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6
Q

what type of innate immune cells activate the adaptive immunity

A

dendritic

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7
Q

what type of barriers are involved in the innate response

A

physical, physiochemical, chemical and biological

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8
Q

what do the barriers of the innate immunity aim to do

A

prevent pathogen entry and limit growth

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9
Q

what are the physiological barriers in the innate immunity

A
  • diarrhoea: expels miscorbes
  • vomiting
  • coughing
  • sneezing
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10
Q

what are the chemical barriers in the innate immunity

A
  • low pH (skin, stomach and vagina)

- antimicrobial molecules

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11
Q

what are the biological barriers in the innate immunity

A
  • normal flora
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12
Q

what is the normal flora

A

non pathogenic molecules (as long as they don’t change location) found in the body

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13
Q

where is normal flora found

A
  • skin
  • mouth/throat
  • nasopharynx
  • GI tract
  • vagina
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14
Q

what are the advantages of the normal flora

A

competes with pathogens for attachment sites and resources
produce antimicrobial chemicals
synthesise vitamins

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15
Q

give examples of antimicrobial molecules

A

IgA, lysozymes, mucus and gastric acid

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16
Q

give examples of normal flora that inhabit the skin

A
  • staphylococcus aureus

- staphylococcus epidermidis

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17
Q

give examples of normal flora what inhabit the nasopharynx

A
  • streptococcus pneumonia

- Neisseria meningitidis

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18
Q

when are there problems with the normal flora

A
  • when its displaced from its normal location to a sterile location
  • when it overgrows and becomes pathogenic when the host is immunosuppressed
  • when it is depleted by antibiotics
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19
Q

what causes the displacement of normal flora

A
  • breaching the skin
  • the fecal oral route
  • fecal-perineal-urethral route
  • poor dental hygiene
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20
Q

how can the skin be breached

A

IV lines, burns, surgery and injection drug users

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21
Q

what is involved in the second line of defence in the innate immunity

A

factors that will contain and clear the infection:

  • phagocytes
  • chemicals
  • inflammation
22
Q

what are the 3 main phagocytes

A

macrophages
monocytes
neutrophils

23
Q

what do macrophages do

A
  • phagocytosis
  • antigen presenting to T cells
  • produces cytokines
24
Q

what do monocytes do

A

recruited to site of infection and differentiate into macrophages

25
Q

what do neutrophils do

A

recruited by cytokines and ingest bacteria

increase during infection

26
Q

what happens to neutrophils after phagocytosis

A

they die

27
Q

what do basophils and mast cells do

A

activators of inflammation

important in allergic repsonse

28
Q

what do eosinophils do

A

kill parasites

29
Q

what do natural killer cells do

A

kill all abnormal host cells

30
Q

what do dendritic cells do

A

present antigens to T cells

31
Q

what is on the surface of microbes which is recognised by immune cells

A

Pathogen associated molecular patterns (PAMPs)

32
Q

what are the receptors on pathogens that bind to PAMPs

A

Pathogen recognition receptors (PRRs)

33
Q

what is opsonisation

A

coating proteins called opsonins to the surface of microbes leading to enhanced attachment of phagocytes and clearance of microbes

34
Q

give an example of a complement protein used in opsonisation

A

C3b

35
Q

give an example of a antibody which is used as an opsonin

A

IgG

36
Q

give an example a of acute phase protein which are used as opsonins

A

c-reactive protein

37
Q

what 2 things allows the recognition of microbes by phagocytes

A

opsonins and PAMPs

38
Q

outline phagocytosis

A
  • chemotaxis and adherence of pathogen
  • ingestion
  • phagosome formation
  • phagolysosome formation
  • digestion with enzymes
  • formation of residual body containing indigestible material
  • discharge of waste
39
Q

what is oxygen dependant pathway

A

where toxic oxygen products e.g. hydrogen peroxide and nitric acid kill pathogens directly

40
Q

what is oxygen independent phagocytosis

A

were lysozymes and hydrolytic enzymes digest the microbe

41
Q

what 3 actions does the complement system produce

A
  • opsonisation
  • inflammation
  • attacking membranes
42
Q

what 2 pathways activate the complement system

A
    • alternative pathway: initiated by cell surface constituents e.g. endotoxins
  • MBL pathways: when mannose binding lectin binds to mannose containing residues of proteins found on microbes
43
Q

which complement proteins are used in membrane attacking

A

C5-C9

44
Q

what are the antimicrobial actions of TNF and interleukin 1 and 6

A
  • cause the hypothalamus to increase body temp
  • cause inflammatory actions such as vasodilation, vascular permeability
  • cause neutrophil mobilisation in bone marrow
  • liver produces acute phase response proteins e.g. CRP which are also opsonins so activates complement cascade
45
Q

what is chronic granulomatous disease

A

neutrophils don’t function properly so theres no respiratory burst

46
Q

what can cause a decrease in neutrophil number

A

chemotherapy
drugs
leukaemia

47
Q

what bacteria causes thrush when it goes into the vagina

A

candida albicans

48
Q

what bacteria causes colitis when it goes into the intestine

A

clostridium difficile

49
Q

what is Antibiotic prophylaxis

A

Antibiotic prophylaxis refers to the prevention of infection complications using antimicrobial therapy

50
Q

which high risk patients can serious infections be caused by displacement of normal flora

A
  • asplenic patients
  • damage valves
  • previous infective endocarditis