Microbiology Chapter 23 Immune Disorders.txt

  1. Type I: anaphylactic hypersensitivity
    • IgE
    • Mast cells
  2. Type II: Cytotoxic hypersensitivity
    • Rh disease
    • Thrombocytopenia
  3. Type 1 IgE mediated hypersensitivity
    • Type I: anaphylactic hypersensitivity
    • All the characteristics of a humoral immune response
    • Allergen enters body and the body responds as if the allergen is a dangerous antigen or pathogen
    • The allergen is taken up by antigen-presenting cells
    • B cells are stimulated to mature into plasma cells which produce IgE
    • IgE binds to mast cells and basophils
    • Second time you are exposed, IgE is already bound to mast cells.
    • Histamine is released
  4. Allergen
    A substance which triggers an allergic reaction in the body
  5. Mast cells
    • Are connective tissue cells found in the respiratory and gastrointestinal tracts and near blood vessels
    • Filled with 500-1500 granules containing histamine and other physiologically active substances
    • The difference between mast cells and basophils is mast cells are found outside of the CV system
  6. Basophils
    Circulating leukocytes in the blood that are also rich in granules
  7. Histamine
    • The most important mediator of allergic reactions
    • A deriviative of the amino acid histidine
    • Once in the bloodstream, histamine circulates to the body cells and attaches to the histamine receptors present on most body cells
    • Constricts smooth muscles cells
  8. Systemic anaphylaxis
    • Most Dangerous Form of a Type I Hypersensitivity
    • Allergens in the bloodstream can trigger mast cell degranulation that contracts smooth muscle
    • Small veins constrict and capillary pores expand, forcing fluid into the tissues
    • A drop in blood pressure, edema, and rash occur
    • Contractions in the gastrointestinal tract and bronchial muscles cause cramps and shortness of breath
    • The lungs fill with carbon dioxide
    • This can cause death by asphyxiation in 10-15 minutes
  9. Atopic Disorders
    Are the Most Common Form of a Type I Hypersensitivity
  10. Atopic disease is a
    • Common (seasonal) allergy caused by the inhalation of pollen
    • Year-round allergies can result from chronic exposure to allergens
  11. Food allergies can cause symptoms like:
    • swollen lips
    • abdominal cramps
    • nausea
    • diarrhea
    • hives
    • anaphylaxis
  12. Physical factors that can cause allergies include:
    • extreme temperatures
    • sunlight
    • sweating
  13. Exercise can cause allergies in the form of
    An asthma attack
  14. Allergic Reactions Also Are Responsible for Triggering
    Many Cases of Asthma
  15. Asthma can be caused by
    airborne allergens, exercise, or cold temperature
  16. Degranulation of mast cells releases
    • mediators in the lower respiratory tract, causing:
    • brochoconstriction
    • vasodilation
    • mucus buildup
  17. Recruitment of eosinophils and neutrophils into the lower respiratory tract can cause:
    • tissue injury
    • airway blockage
  18. Uticaria
    Hives with red zones
  19. Why Do Only Some People Have IgE-Mediated Hypersensitivities?
    • Atopic people may lack sufficient IgA-secreting lymphocytes to block antigen stimulation in IgE
    • Atopic people may have defective suppressor T cells, allowing for more IgE production
  20. Allergies may help expel pathogens through:
    • sneezing
    • gastrointestinal tract contractions
  21. Therapies Sometimes Can Control
    Type I Hypersensitivities
  22. Desensitization therapy involves a series of injections of allergens which may
    • Cause gradual reduction of granules in sensitized mast cells
    • Cause production of IgG antibodies that neutralize allergens (blocking antibodies)
  23. Treatments
    • Monoclonal antibodies
    • Antihistamines
    • Corticosteroids
  24. Monoclonal antibodies can be used to
    • Dislodge IgE from mast cells and basophils
    • This prevents allergic reactions
  25. Antihistamines block
    The effect of histamine
  26. Corticosteroids are
    • Inhaled through the nose to relieve symptoms
    • Some also block mediator release
  27. Type II Cytotoxic Hypersensitivity
    • A cell damaging, humoral immune response occurring when IgG reacts with antigens on the surfaces of cells
    • It occurs when IgG reacts with antigens, often activating complement
  28. Hemolytic disease
    • Type II. Rh disease
    • When an Rh+ man and an Rh- woman produce an Rh+ child, the mom can produce antibodies against the newborns blood when placenta rips.
    • When the second child is born, mom already has antibodies and they destroy some of the fetus�s red blood cells leading to anemia and hemolytic disease.
  29. Flare
    Zone of redness
  30. Wheal
    Rash consisting of central puffiness
  31. Thrombocytopenia
    • Platelets are destroyed
    • Aspirin, antibiotics, and antihistamines can bind to platelets. Body reacts to the foreign substance and sends in the IgG
  32. Type III: immune complex hypersensitivity
    • Serum sickness (arthus reaction)
    • Rheumatoid arthritis
  33. Immune hypersensitivity 1-3 can occur
    In a matter of minutes
  34. Type IV: cellular hypersensitivity
    Cell mediated reaction takes 24-72 hours
  35. Induration
    Thickening and drawing of the skin
  36. Erythema
  37. Infection allergy
    Like the TB test
  38. Contact dermatitis
    Poison ivy
Card Set
Microbiology Chapter 23 Immune Disorders.txt
Microbiology Chapter 23 Immune Disorders