Brainscape's Knowledge GenomeTM

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


See full index

Foundations of Medicine JMO > Hypersensitivity > Flashcards

Hypersensitivity Flashcards

1
Q

What is hypersensitivity?

A

An immune response that results in bystander damage to the self

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

What are the 2 phases of hypersensitivity?

A

Sensitisation phase - first contact to stimulus
Pathological phase - further contact causing disease

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

How many hypersensitivity classes are there in Gel and Coomb’s classification?

A

5
Type I,IIa,IIb,III,IV

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

What is type I hypersensitivity?

A

An allergic immune response causing atopic dermatitis, food allergies and allergic asthma

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

What was the allergic immune response initially formed to destroy?

A

Parasitic infection

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

What cells are found in a type I hypersensitivity response?

A

Mast cells
B-cells
Th2 cells
Eosinophils
IgE antibodies

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

What occurs during the sensitisation stage of a type I hypersensitivity reaction?

A

Allergen stimulates dendritic cells
Dendritic cells stimulate Th2 cell formation
Dendritic cells stimulate Tfh cell formation
Allergen + Tfh cells stimulate B cell formation
Th2 cells produce IL-5 to bone marrow
Th2 cells produce IL-4 and IL-13
IL-5 causes eosinophilia
IL-4 and IL-13 stimulate IgE B cells which release IgE
Basophils and mast cells take up excess IgE antibodies as receptors

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

What is eosinophilia?

A

An abnormally high level of eosinophils

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

What occurs during the pathological stage of a type I hypersensitivity reaction?

A

2nd allergen contact
Allergen binds to IgE receptors on mast cells and basophils
Degranulation releases histamine and tryptase (vasoactive mediators)
Degranulation releases pro-inflammatory cytokines and leukotrienes

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

What is the effect of histamine and heparin?

A

Increased vascular permeability and smooth muscle contraction

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

What is the effect of ECF-A (Eosinophil Chemotactic Factor)?

A

Eosinophil chemotaxis (Attraction)

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

What is the effect of NCF-A (Neutrophil Chemotactic Factor)?

A

Neutrophil chemotaxis (Attraction)

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

What is the effect of proteases such as tryptase and chymase in a hypersensitivity reaction?

A

Bronchial mucus secretion
Degradation of blood vessel basement membrane

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

What is the effect of platelet-activating factor?

A

Platelet aggregation and degranulation
Contraction of pulmonary smooth muscle

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

What is the effect of leukotrienes (Slow reactive substance of anaphylaxis (SRS-A))?

A

Increased vascular permeability
Contraction of pulmonary smooth muscle

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

What is the effect of prostaglandins?

A

Vasodilation
Contraction of pulmonary smooth muscles
Platelet aggregation

17
Q

What is the effect of bradykinin?

A

Increased vascular permeability
Smooth muscle contraction

18
Q

What are some of the effects of cytokines?

A

Systemic anaphylaxis
Increased expression of adhesion molecules
Increased IgE production

19
Q

What are some common features of a type I hypersensitivity reaction?

A

Asthma
Urticaria - hives (Itchy red rash)
Angioedema - swelling under the skin
Allergic rhinitis - hay fever
Allergic conjunctivitis
Diarrhoea
Vomiting
Anaphylaxis

20
Q

How does sodium cromoglicate treat a type I hypersensitivity reaction?

A

It prevents mast cell degranulation

21
Q

How does montelukast treat a type I hypersensitivity reaction?

A

It is a leukotriene receptor antagonist so prevents leukotriene induced symptoms such as airway constriction

22
Q

How does prednisolone treat a type I hypersensitivity reaction?

A

It is a steroid
It decreases the immune sresponse and inflammation
e.g. reduced Th2 cells

23
Q

What treatments are used for a type I hypersensitivity reaction?

A

Steroids
Adrenaline
Immunotherapy
Anti-inflammatory agents
Anti-histamines
Leukotriene receptor antagonists
Allergen avoidance

24
Q

What is a Type IIa hypersensitivity reaction?

A

A reaction in which IgM/IgG antibodies are directed towards antigens present on cell surfaces or the ECM, causing the destruction of antigen-positive cells

25
Q

What is a Type IIb hypersensitivity reaction?

A

A reaction in which IgM/IgG antibodies are directed towards antigens present on cell surfaces or the ECM, causing the stimulation of the antigen-positive cells

26
Q

What are examples of type IIb hypersensitivity reactions?

A

Grave’s disease - hyperthyroidism due to stimulation of TSH (Thyroid Stimulating Hormone) receptors
Myasthenia gravis - loss in muscle function due to blocking of acetylcholine receptors in neuromuscular junctions

27
Q

What is a type III hypersensitivity reaction?

A

A large scale inflammation reaction, caused by the trapping of soluble immune complexes (Antibodies + antigens) on the surrounding basement membrane, leading to neutrophils causing tissue damage. It can lead to tissue death and haemorrhage

28
Q

What is an example of a type III hypersensitivity reaction?

A

Acute hypersensitivity pneumonitis
Immune complexes deposited in alveolar and bronchiole walls

29
Q

What is a type IV hypersensitivity reaction?

A

AKA Delayed Type Hypersensitivity reactions (DTH)
CD4+ T-cells activated by antigen
Form effector Th1 cells
Macrophage recruitment
Reactivation of Th1 cells by macrophages
Reactivation of macrophages by Th1 cells
Tissue damage due to inflammation

30
Q

What is dyspnoea?

A

laboured breathing

Foundations of Medicine JMO (56 decks)

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