Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Pathology and Immunity > Hypersensitivity > Flashcards

Hypersensitivity Flashcards

1
Q

what is a hypersensitivity reaction

A

this is a state of altered reactivity in which the body reacts with an immune response to a foreign agent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is an allergen

A

a foreign antigen that causes an allergic reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

how can allergens be

A

airbone
food
medication

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are some airborne allergens

A

pollen or dust

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

how are intolerances and allergies different

A

allergies involve the immune system but intolerances involve the digestive system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what are the four types of hypersensitivity

A

I
II
III
IV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

describe type I hypersensitivty

A

this is IgE mediated and involves mast cells and basophils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what are examples of type 1 hypersensitive reactions

A

cutaneous atopy and anaphylaxis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

describe type II hypersensitive reactions

A

cytotoxic responses involving NK cells, complement and T cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is an example of type II hypersensitivity

A

haemolytic anaemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is an example of type III hypersensitive reactions

A

arthus reaction
serum sickness
oral erythema multiforme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

describe type III hypersensitive reactions

A

these are immune complex responses involving complement and neutrophils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is an example of a type IV hypersensitive reactions

A

tuburculosis and crohns

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

describe type IV hypersensitivity

A

cell mediated response reaction involving t cells and macrophages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

explain the form of allergens

A

allergens tend to be proteins and have the ability to elicit an immune response but some can be haptens ie non proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

describe hapten allergens

A

these are small molecules that can be recognised by a specific antibody but they cannot elicit an immune response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

how do haptens elicity antibody or t cell responses

A

they are small and first must be chemically linked to a protein molecule called a carrier

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is it called when haptens bind to carrier proteins

A

conjugation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

which is the most common type of hypersensitivity

A

type I

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what produces IgE

A

b cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what do mast cells and basophils release in type I reactions

A

histamines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

describe how type I IgE mediated hypersensitivity works

A

as allergens binds to IgE antibodies, IgE cross linking induces degranulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what can cause type I hypersensitive reactions

A

anaphylaxis
hay fever
hives
exzema
allergies to certain foods

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

where do antigens bind on antibodies

A

the FC receptor region

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what is an important thing to note about eosinophils and basophils in the context of the exam

A

they are parasite eaters involved in allergic reactions
basophils are involved in allergic reactions alongside mast cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what do b cells produce in response to microbial antigens

A

IgM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

when do b cells carry out a class switch and what do they switch to

A

when responding to specific antigens
usually IgG but in allergic reactions it is IgE in order to drive the allergic response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

how does IgE work

A

it binds to specific receptors on mast cells and basophils to stimulate and result in degranulation of histamine and other chemical mediators into the surrounding tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

where does IgE bind to on mast cells

A

Fc receptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

where does IgE bind on basophils

A

CD63

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

what is elicitation

A

this is when IgE recognises an allergen and next exposure it will bind rapidly and cause immediate degranulation of immune cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

list the stages to type I hypersenstivity reactions

A
  • upon first exposure to the allergen, APC prcesses the antigen and presents it to a TH2 cell
  • TH2 cells release Il4 and Il12 to activate the b cells
  • b cells will proliferate and differentiate into plasma cells to synthesise and secrete IgE antibody
  • IgE binds to mast cells by Fc region and sensitises the mast cells
  • upon subsequent exposure to the allergen, mast cells with IgE bind to antigen and release inflammatory molecules, resulting in allergy symptoms
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

what are the main roles of histamine

A

vasodilation
increased vascular permeability of blood vessels
smooth muscle contraction
bronchoconstriction
neurotransmission (sensation of itching in allergies)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

what is anaphylaxis

A

widespread allergic reaction to a particular allergen found throughout the body through histamine and anaphylatoxins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

what is atopy

A

general predisposition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

what is a cutaneous reaction

A

one that is localised to a particular tissue

37
Q

examples of cutaneous hypersensitivity reactions

A
  • allergic rhinitis
  • atopic dermatitis
  • asthma
  • allergic reaction to chlorhexidine
38
Q

what does systemic anaphylaxis lead to

A

anaphylactic shock

39
Q

describe what the body undergoes during systemic anaphylaxis

A

mast cell degranulation releases histamine
complement system produces anaphylatoxins through the classical pathway
the two molecules have widespread impacts on respiration and cardiovascular health

40
Q

what are the two key symptoms of anaphylactic shock

A
  • narrowing of the larynx where there is laryngeal oedema
  • tightening of the bronchioles to narrow the airways and reduce breathing
41
Q

what type of hypersensitivity is associated with skin patch tests

A

type I

42
Q

describe the tests that can be taken to determine type I hypersensitivity

A

skin patch
blood test
oral challenge

43
Q

how does a skin patch test work

A

wheal and flare reaction
to help identify the allergen

44
Q

how does a blood test work to determine type I hypersensitivity

A

measures IgE levels in the blood

45
Q

how does oral challenge hypersensitivity

A

diagnoses food allergies

46
Q

what are antihistamines

A

histamine receptor agonist

47
Q

what is hydrocortisone

A

this blocks histamine synthesis

48
Q

what does epinephrine do

A

this reverses the effects of granules through vasodilation

49
Q

describe the possible immunological treatments for type I hypersensitivity

A

hyposensitivity through injecting allergens
IgE to IgG production

50
Q

what is the main treatment for type I hypersensitivity

A

just avoiding the allergy

51
Q

what is the classification system that defines the four types of hypersensitivity

A

gell and coombs

52
Q

what mediates type I allergies

A

IgE

53
Q

how can type I hypersensitivity be defined

A

either localised or systemic
localised is cutaneous atopy
systemic is anaphylaxis

54
Q

which molecules drive type I hypersensitive reactions

A

histamine and anaphylatoxins

55
Q

describe type II hypersensitivity

A

this involves activation of complement by antibody binding to an antigen

56
Q

which antibody is involved in type II hypersensitivity

A

not IgE

57
Q

what are the antigens involved in type II hypersensitivity

A

cell surface auto antigens or allergens

58
Q

how are infected cells lysed during type II hypersensitivity

A

cell is lysed by membrane attack complex formation from the complement system and antibody dependent cellular cytotoxicity

59
Q

what produces autoantigens

A

the host

60
Q

what are the type II hypersensitivity reactions driven against

A

host tissues or components of the human body. cells are lysed by membrane attack complex which is formed from the complement cascade or through antibody dependent cellular cytotoxicity

61
Q

which cells are involved in antibody dependent cytotoxicity

A

natural killer cells or CD8+ t cells

62
Q

what is the ultimate response of type II hypersensitivity

A

lysis of the cell

63
Q

describe the type II hypersensitive response when there is transfusion of mis matched blood type

A
  • donated type A blood with type A antigens enters the bloodstream of type B recipient
  • anti-A antibodies in plasma of type B recipient binds to donated type A red blood cells
  • bound anti-A antibodies activate complement cascade, causing hemolysis and release of haemoglobin
64
Q

what happens to erythrocytes when they bind antierythrocyte autoantibodies

A
  • autoantibodies activate complement; antibody and complement coated erythrocytes are targeted for destruction by macrophages in the spleen
  • complement activation and intravascular haemolysis
65
Q

what are the two methods of erythrocyte destruction when there is mismatched transfusion

A

phagocytosis or lysis

66
Q

what is autoimmune haemolytic anaemia

A

this is where the immune system generates antibodies and cell mediated responses against its own red blood cells which is bad as any circulating red blood cells will be targeted and destroyed

67
Q

what is type III hypersensitivity

A

this involves reactions against soluble antigens or allergens circulating in the blood
antibody antigen immune complexes are deposited in tissues which leads to immune responses

68
Q

describe type II immune complex mediated hypersensitivity

A

immune complexes are deposited in tissues to activate a complement which attracts neutrophils to the site

69
Q

what are examples of type III complex mediated hypersensitivity

A

rheumatoid arthritis and glomerulonephritis

70
Q

what is arthus reaction

A

localised hypersensitivity reaction whereby antibody antigen complexes are localised in blood vessel walls
can arise from injected particules or from inhaled or ingested allergens

71
Q

what is serum sickness

A

this is a systemic form of arthus reaction where the antibody antigen complexes lodge in many different tissues

72
Q

what is oral erythema multiforme

A

this is a condition characterised from blistering of the oral mucosa
there is deposition of immune complexes in the oral mucous membrane
is usually viral or drug related

73
Q

what are the immune complexes leading to oral erythema multiforme

A

IgM bound immune complexes

74
Q

describe type IV hypersenstivity

A

this is t cell mediated hypersensitivity that does not involve antibodies
it has a delayed response as it involves the recruitment of t cells from adaptive immunity
t cell reaction is localised at the site of antigen exposure and it involves both CD4+ and CD8+ t cells

75
Q

how can t cells drive type IV hypersensitivity reactions

A

CD4+ t cells damage via macrophages - indirect
CD8+ t cells damage cells through cytotoxicity - indirect

76
Q

summarise type IV cell mediated hypersensitivity

A

cytokines secreted by t helper cells activate macrophages and cytotoxic t cells

77
Q

what are examples of type IV cell mediated hypersensitivity

A

contact dermatitis
diabetes mellitus type I
multiple sclerosis

78
Q

what is tuberculosis

A

this is granulomas in lung tissue due to type IV hypersensitivty

79
Q

what is an oral disease caused by type IV hypersensitivity reactions

A

orofacial granulomatous

80
Q

what forms granulomas

A

macrophages and t cells

81
Q

why do granulomas form

A

they contain infectious agents

82
Q

what does type II lead to

A

complement activation and antibody dependent cell mediated cytotoxicity

83
Q

which hypersensitivity does this describe: IgE mediated response involving mast cells, basophils and b cells that responds to an allergen or hapten

A

type I

84
Q

which hypersensitivity does this describe: IgG or IgM mediated response leading to complement activation and antibody dependent cell mediated cytotoxicity

A

type II

85
Q

which hypersensitivity does this describe: an antibody antigen mediated response often in vasculature but can also occur in tissues

A

type III

86
Q

which type of hypersensitivty reaction causes oral erythema multiform

A

type III

87
Q

which hypersensitivity does this describe: t cell mediated with no requirement for antibodies

A

type IV

88
Q

which type of hypersensitivity reaction causes orofacial granulomatous

A

type IV

Pathology and Immunity (16 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions