Chapter 17: Immunologic Disorder - Type I Hypersensitivity Flashcards
1
Q
What is hypersensitivity? (2)
A
- an antigenic response beyond that considered normal
- immune response to an allergen
2
Q
What is an allergen?
A
- an antigen that causes hypersensitivity
3
Q
What is Type I hypersensitivity?
A
- anaphylactic response
4
Q
What occurs during the 1st encounter of anaphylactic response? (2)
A
- first encounter with Allergen causes B cells differentiate into plasma and memory cells
- plasma cells make a IgE, which binds to mast cells or basophils
5
Q
Are there any symptoms during the first encounter of type I hypersensitivity?
A
no
6
Q
what occurs in the 2nd encounter of type one anaphylactic response? (3)
A
- IgE molecules bind to antigen
- Mast cell or basophils degranulate, releasing histamine
- histamine triggers inflammation
7
Q
What does histamine trigger in terms of inflammation? (4)
A
- vasodilation, swelling, redness
- itchiness
- mucous production - tears, runny nosr
- difficulty breathing
8
Q
In the 2nd encounter of type 1, what happens if the allergen is spread throughout the body? (2)
A
- sudden decrease in blood pressure
- anaphylactic shock
ex. food allergies (peanuts)
9
Q
What are three ways to treat type 1 hypersensitivity?
A
- Antihistamine
- Epinephrine
- Allergy shots
10
Q
What do antihistamines do? (3)
A
- blocks the action of histamines
- histamines are still produced but cannot trigger imflammation
- works well for mild symptoms like hay fever
11
Q
What does epinephrine (epi-pen) do?
A
- used to treat anaphylactic shock
- acts as a vasoconstrictor - increases BP
12
Q
How long does epinephrine last for?
A
20-30 minutes
- time to administer intravenous antihistamines
13
Q
What are allergy shots?
A
- injected like a vaccine
- increasing doses of the antigen over a few years
14
Q
How do allergy shots work?
A
- induces memory cells that make IgG instead of IgE
- IgG will bind and neutralize antigen before it can bind to IgE
- thus prevents the release of histamine
