Immune System Disorders Flashcards
hypersensitivity occurs when
the immune system causes tissue damage because it reacts to an antigen that most people would tolerate
allergy is
a reaction to an environmental allergen such as mold, dust, pollen, drugs, vaccines, venoms, cosmetics, and food
initial contact with an allergen produces
no symptoms, but it sensitizes the person to that particular allergen
Type 1 (immediate, acute) hypersensitivity occurs
within seconds after a person gets re-exposed to an allergen to which he/she is sensitive and it lasts about 30 minutes
during Type 1 hypersensitivity abnormally large number of
helper cells differentiate and stimulate B cells to mature and secrete IgE antibodies
secreted IgE antibodies
bind the allergen to the surface of mast cells and basophils and stimulate these cells to release histamine and other inflammatory chemicals-causes vasodilation, smooth muscle spasms, excessive production of mucus
localized effects of Type 1 hypersensitivity include
swelling, watery eyes, runny nose, and hives
-all might be relieved with histamines
food or drug allergies may cause
gastrointestinal cramping, vomiting, and diarrhea
asthma is
triggerd by inhaling allergens
anaphylactic shock
is a severe systemic reaction that produces sudden skin reddening, intense itching, respiratory distress, cardiovascular failure
anaphylactic shock typically occurs
when an allergen enters the blood of an individual who is hypersensitive
death may result from anaphylactic shock unless
epinephrine is administered to dilate bronchioles, increase cardiac output, restore blood pressure
type II (cytotoxic) hypersensitivity occurs when********
IgG or IgM antibodies attack antigens on blood cells or tissue cells, which stimulates macrophages to phagocytize and destroy them
Type III (immune complex) hypersensitivity occurs when
antigen-antibody complexes form beneath the endothelium of blood vessels and activate the complement system and trigger intense inflammation
