Sept. 18, 2019 Flashcards
What is HYPERSENSITIVITY?
An inappropriate/exaggerated IR
T or F:
It is good to have a HYPERSENSITIVE or exaggerated IR
F
Appearing in excess is bad
What ANTIBODY is involved in a TYPE 1 HYPERSENSITIVITY reaction?
IgE (IMMUNOGLOBULIN E)
TYPE 1 is a ______ form of HYPERSENSITIVITY.
common
A HYPERSENSITIVE reaction occurs d/t what?
An ALLERGEN
Is TYPE 1 ACUTE or CHRONIC?
ACUTE, rapid onset; w/in minutes
Explain what happens during the first contact between an ALLERGEN and a MAST CELL
- T-HELPER-2 CYTOKINES are produced
- B-CELLS are stimulated
- PLASMA CELL formation
- IgE production
- IgE attaches to and sensitizes MAST CELL
Explain what happens during second contact between and ALLERGEN and a MAST CELL
- ALLERGEN binds to IgE on surface of MAST CELL
- INFLAMMATORY MEDIATORS are released
- INFLAMMATION occurs
- EYTHEMA, PRURITUS, swelling, etc.
Define SHOCK
ACUTE HYPOPERFUSION d/t CARDIOVASCULAR failure, resulting in HYPOXIA
When does ANAPHYLACTIC SHOCK occur?
Following severe allergic reaction
Explain what happens during ANAPHYLACTIC SHOCk after an ALLERGEN is introduced to the body
- ALLERGEN binds to IgE on surface of MAST CELL
- MEDIATORS are released
- Extreme SYSTEMIC VASODIL
- Large inc in CAPILLARY PERMB
Why is B volume dec during ANAPHYLACTIC SHOCK?
Because excess amounts of FLUID are lost due to the inc of CAP PERMB
What causes low BP during ANAPHYLACTIC SHOCK?
Low BP is d/t SYSTEMIC VASODIL which dec resistance
Where can EDEMA be found during ANAPLHYLACTIC SHOCK>
Everywhere
What causes SEPTIC SHOCK?
Severe INFECTION
What kind of antibody can be found during TYPE 2 HYPERSENSITIVITY reaction?
IgG or IgM
TYPE 2 HYPERSENSITIVITY reaction can also be referred to as a _________ or _____ _______ reaction
CYTOTOXIC, TISSUE SPECIFIC
Does TYPE 2 occur in response to ENDOGENOUS or EXOGENOUS ANTIGENS
Both
What is an example of a TYPE 2 HYPERSENSITIVE reaction?
Incompatible B transfusion
What kind of HYPERSENSITIVITY reaction is TYPE 3?
IMMUNE COMPLEX HYPERSENSITIVITY
Ag + Ab = ?
AgAb aka the IMMUNE COMPLEX
WHat happens if the IMMUNE COMPLEX is not removed?
It deposits in tissues, often the ENDOTHELIUM
Why is there tissue damage in TYPE 3 reactions?
Because COMPLEMENT is activated, resulting in INFLAMMATION and there is ALWAYS tissue damage w INFLM
What makes TYPE 4 HYPERSENSITIVITY different from the rest?
It is CELL mediated as opposed to ANTIBODY mediated
Explain the process leading up to INFLM in TYPE 4 reactions
- MACROPHAGE presents Ag to T-CELL
- T-CELL is sensitized to Ag
- CYTOTOXIC T-CELLS are activated
- destroy the Ag-bearing CELL
- INFLM and tissue damage
How many types of TYPE 4 reactions are there? What are they?
2, DIRECT and INDIRECT
What CELL is required for INDIRECT TYPE 4 reactions?
LYMPHOKINES
What is AUTOIMMUNITY?
When IMMUNE SYSTEM loses the ability to differentiate foreign CELLS from it’s own, it will target it’s own CELLS and Ags
What are 3 reasons that self-tolerance may be lost?
1) MOLECULAR MIMICRY
2) Abn T-CELL Fx
3) Exposure of sequestered Ags
Why might MOLECULAR MIMICRY result in AUTOIMMUNITY?
If the EPITOPE on a foreign CELL is similar to an EPITOPE on a self-CELL, this may confuse the IMMUNE SYS and result in AUTOIMMUNITY
Why might abn T-CELL Fx result in AUTOIMMUNITY?
In a normal IMMUNE RESPONSE, T-CELLS create CYTOTOXIC T-CELLS to destroy the foreign Ags, after destruction is complete, T-CELLS must be suppressed, if not, they will continue to destroy CELLS, even if they are self-CELLS.
Why might exposure of sequestered CELLS result in AUTOIMMUNITY?
If CELLS were sequestered (hidden) at birth, and are exposed later in life as a result of injry or disease, they will be identified as foreign CELLS because the IMMUNE SYS was not “introduced” to them until much later in life. They will be destroyed as if they were foreign CELLS.
