NU545 CHAPTER 9 EXAM QUESTIONS AND ANSWERS
WITH COMPLETE SOLUTIONS LATEST UPDATE
Allergy:
Is an exaggerated response against
an environmental antigen.
Autoimmunity:
Is a misdirected response against the host's own cells.
Alloimmunity:
Is directed against beneficial foreign tissues (e.g., transfusions, transplants)
Hypersensitivity reactions:
An altered immunologic response to an antigen that results in disease or damage to the host.
Sensitization:
Adequate amount of antibodies or T cells is available to cause noticeable reaction on reexposure to
antigen.
Immediate hypersensitivity reaction:
- Reaction that occurs within minutes to a few hours
- Anaphylaxis: systemic or cutaneous
Delayed hypersensitivity reaction:
,- Reaction that takes several hours to appear
- Maximum severity occurs days after reexposure to the antigen
Hypersensitivity reactions: Characterized by the immune mechanism - Type I
IgE-mediated
Hypersensitivity reactions: Characterized by the immune mechanism - Type II
Tissue-specific reactions
Hypersensitivity reactions: Characterized by the immune mechanism - Type III
Immune-complex mediated
Hypersensitivity reactions: Characterized by the immune mechanism - Type IV
- Cell mediated
- Delayed
Type I: IgE-Mediated Hypersensitivity Reactions
Against environmental antigens (allergens).
IgE binds to:
crystalline fragment (Fc) receptors on the surface of mast cells; cross linking causes the release of
histamine from mast cell degranulation.
- H1 and H2 receptors
- Increases chemotactic activity
Cytotropic antibodies bind to:
the cell surface and reagins are antibodies that can bind to skin.
, Type I: IgE-Mediated Hypersensitivity Reactions: Manifestations from H1
- Bronchial constriction
- Edema
- Vasodilation
Type I: IgE-Mediated Hypersensitivity Reactions: Manifestations from H2
- Increases gastric secretions.
- Decreases the release of histamine from mast cells and basophils.
Type II: Tissue-Specific Hypersensitivity Reactions
Specific cell or tissue (tissue-specific antigens) is the target of an immune response.
Type II: Tissue-Specific Hypersensitivity Reactions: Five mechanisms
- Cell is destroyed by antibodies and complement.
- Cell destruction occurs through phagocytosis.
- Neutrophils release granules.
- Antibody-dependent cell-mediated cytotoxicity is present.
- Causes target cell malfunction.
Type III: Immune Complex-Mediated Hypersensitivity Reactions
- Complexes are formed in the circulation and deposited later in vessel walls or extravascular tissues.
- Is not organ specific.
Type III: Immune Complex-Mediated Hypersensitivity Reactions: Damage results from
Damage results from complement activation and neutrophil lysosomal enzymes.
Type III: Immune Complex-Mediated Hypersensitivity Reactions: Immune complex clearance
WITH COMPLETE SOLUTIONS LATEST UPDATE
Allergy:
Is an exaggerated response against
an environmental antigen.
Autoimmunity:
Is a misdirected response against the host's own cells.
Alloimmunity:
Is directed against beneficial foreign tissues (e.g., transfusions, transplants)
Hypersensitivity reactions:
An altered immunologic response to an antigen that results in disease or damage to the host.
Sensitization:
Adequate amount of antibodies or T cells is available to cause noticeable reaction on reexposure to
antigen.
Immediate hypersensitivity reaction:
- Reaction that occurs within minutes to a few hours
- Anaphylaxis: systemic or cutaneous
Delayed hypersensitivity reaction:
,- Reaction that takes several hours to appear
- Maximum severity occurs days after reexposure to the antigen
Hypersensitivity reactions: Characterized by the immune mechanism - Type I
IgE-mediated
Hypersensitivity reactions: Characterized by the immune mechanism - Type II
Tissue-specific reactions
Hypersensitivity reactions: Characterized by the immune mechanism - Type III
Immune-complex mediated
Hypersensitivity reactions: Characterized by the immune mechanism - Type IV
- Cell mediated
- Delayed
Type I: IgE-Mediated Hypersensitivity Reactions
Against environmental antigens (allergens).
IgE binds to:
crystalline fragment (Fc) receptors on the surface of mast cells; cross linking causes the release of
histamine from mast cell degranulation.
- H1 and H2 receptors
- Increases chemotactic activity
Cytotropic antibodies bind to:
the cell surface and reagins are antibodies that can bind to skin.
, Type I: IgE-Mediated Hypersensitivity Reactions: Manifestations from H1
- Bronchial constriction
- Edema
- Vasodilation
Type I: IgE-Mediated Hypersensitivity Reactions: Manifestations from H2
- Increases gastric secretions.
- Decreases the release of histamine from mast cells and basophils.
Type II: Tissue-Specific Hypersensitivity Reactions
Specific cell or tissue (tissue-specific antigens) is the target of an immune response.
Type II: Tissue-Specific Hypersensitivity Reactions: Five mechanisms
- Cell is destroyed by antibodies and complement.
- Cell destruction occurs through phagocytosis.
- Neutrophils release granules.
- Antibody-dependent cell-mediated cytotoxicity is present.
- Causes target cell malfunction.
Type III: Immune Complex-Mediated Hypersensitivity Reactions
- Complexes are formed in the circulation and deposited later in vessel walls or extravascular tissues.
- Is not organ specific.
Type III: Immune Complex-Mediated Hypersensitivity Reactions: Damage results from
Damage results from complement activation and neutrophil lysosomal enzymes.
Type III: Immune Complex-Mediated Hypersensitivity Reactions: Immune complex clearance
