Pathophysiology Ch. 10
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Pathophysiology Ch. 10
Pathophysiology Immunity Test
Alterations in Immune Function
What are Excessive Immune Responses?
What are Deficient Immune Responses?
What is Autoimmunity?
Person's immune systems goes after self-cells, injuring body tissues
What are the theories of autoimmunity?
Antigenic mimicry theory
-->cells mimic foreign antigens
Sequestered antigen theory
-->some self-antigens are normally hidden from the immune system, revealed due to injury
Thymus gland defect theory
-->self-antigens are not present to T cells during the fetal stage due to a defect in the thymus gland
Defective lymphocyte theories
-->some lyphocytes fail to respond to suppressor cytokines
What are the genetic factors for autoimmunit?
Females are more likely to have a defect.
Higher risk assoc. with certain cytokine patterns, MHC genes
Environmental Factors for autoimmunity.
Viruses or bacteria trigger bad behavior in B or T cells
Environmental or Occupational stress
What are the Treatments for the Symptoms of Autoimmunity?
What are examples of Type I Hypersensitivity?
allergies, eczema, asthma, anaphylactic responses
What is the Etiology of Type I Hypersensitivity?
IgE response to antigens
T cell deficiency increases mast cell degranulation
What is the pathogenesis of Type I Hypersensitivity?
IgE binds to Fc receptors on mast cells
Increased intracellular calcium results in immediate, massive, local mast cell degranulation of proinflammatory mediators
Released mediators cause inflammatory response
What are the clinical manifestations of Type I Hypersensitivity?
What is the Pharmacological management for Type I Hypersensitivity?
What is the Mechanism for Type II Hypersensitivity?
Exposure to antigen on foreign cell surface
Fab portion of IgG or IgM binds to foreign antigen -->makes antigen-antibody complex
Fc region of IgG or IgM stick out
Fc region --> bridge b/n antigen and complement or effector cell
What are two examples of Type II Hypersensitivity?
Hemolytic disease of the newborn
What happens during Type III Hypersensitivity?
Immune and phagocyctic systems fail to effectively remove antigen-antibody immune complexes
Activation of complement
Subsequent tissue inflammation
Destruction of tissue
What activates Type III Hypersensitivity?
Persistent low-grade infections
Inhalation of antigens into alveoli
Autoimmune production of auto-antibodies
What is the difference between Type II and Type III?
Type II- response to tissue-specific antigen on direct cell eath or malfunction of antigen-antibody reactions
Type III- antigen-antibodies precipitate out of fluids and get into tissues
What are some examples of Type III Hypersensitivity?
Immune complex glomerulonephritis
What are the principle effector cells in Type IV Hypersensitivity?
Sensitized T cells react with altered or foreign cells and initiate inflammation
Mast cells involved in early stages
Neutrophils not involved
What are two types of Type IV Hypersensitivity?
Cutaneous Basophil Hypersensitivity
--> Most rapid type
-->Skin Graft reactions and rejection
-->Most familiar type, contact dermatitis
-->Slow reaction; hapten antigen is very small, incomplete
-->Primary defense against intracellular infections
What are Primary Immunodeficiency Disorders?
May be from congenital, genetic, or acquired defects that directly affect immune cell function
What is Severe combined immunodeficiency disorders?
B-cell and T-cell combined disorders
Result from embryonic defects
Usually autosomal recessive, x-linked recessive, defective expression of MHC antigens
What are two T cell Disorders?
-->associated with total or partial loss of thymus gland function
Chronic mucocutaneous candidiasis
What are B cell Disorders?
-IgA bearing lymphocytes fail to become plasma cells, resulting in lack of serum and secretory IgA
What is secondary Immunodeficiency Disorders?
Problems in neuroendocrine and immune system interaction
Excessive neuroendocrine response to stress; increased corticosteroid production increases susceptibility to infection
Immune function impaired as a result of other nonimmune system disorders that secondarily suppress immune function
What are the categories of Allergic Hypersensitivity?
Type one- IgE mediated
Type two- Antibody mediated (tissue specific)
Type three- Complement mediated (immune complex)
Type four- Cell mediated