Part 13: Allergies Flashcards
type 1 hypersensitivity reactions are more commonly known as ___
allergic reaction
type 1 hypersensitivity rxns involve ___ antibodies recognizing an antigen, causing the release of _____ from mast cells
igE; inflammatory mediators
what are the 2 phases of igE mediated rxns?
- sensitization phase and
2. the effector phase
does the first exposure to an allergen typically generate an allergi response? why or why not
no, bc the immune system has never seen the antigen before, so it doesnt know what to do other tahn get rid of it
if a new allergen arrives and there are other cytokines and activated helper T cells, ___ cells may be suspicious of the antigen and make igE antibodies against it. what is this process called?
B ; sensitization
IgE antibodies are found at the surface of ___ cell
mast
resting mast cells are typically found around the membrane barriers of the body such as the ___, ___, ____ and ___
skin, mucous membranes, respiratory tract and GI tract
mast cells participate in ___ immune response, where they recruit other immune cells to the site of injury or infection
early
what happens during a second exposure to an allergen that the body has already been sensitized to ?
IgE antibodies in the mast cells bind to the antigen and cause amst cell degranulation, releasing tons of histamines and other infalmmatory mediators and chemotactic cytokines
the proinflammatory and cytokines produce immediate localized effects such as increased ____ and ___
vasodilation and vascular permeability
what is the purpose of increasing vascular permeability and vasodilation in an allergic rxn?
recruit immune cells
during an allergic rxn , there are increased secretions from the ___ and ___
GI tract, eyes etc
during an allergic rxn, smooth muscle contraction can also occur in response to ___
mast cell degranulation
contraction of smooth muscle in response to allergens results in allergic ____
asthma
when mast cells release ___, ___, and ___ these mediators cause smooth muscle contraction and promote blood vessel permeability allowing immune cells in and the inflammation of the airwyas
histamine, prostaglandins, leukotrienes
t/f immune responses are predictable and repeatable in a patient once the first reaction to allergen occurs
t
allergic rhinitis
upper airways respond to exposure of an inhaled allergen
when an allergic reaction is systemic it can be life-threatening and this is called ___
anaphylaxis
in anaphylactic reaction, exposure to an allergen causes systemic ____, airway ____ and peripheral ___ which can result in respiratory arrest
inflammation; obstruction; edema
what is desensitization therapy?
repeated microdosing of allergen to deplete IgE antibodies and decrease mast cell response over time
what can an allergic rxn look like in the skin?
itchy rash, urticaria
how can an allergic reaction present in the eyes?
redness, watering, itching
how can an allergic reaction present in the lungs?
increased mucous secretions, bronchoconstriction
how can an allergic reaction present in the GI tract?
cramping, bloating, diarrhea, nausea
what happens to BP during anaphylaxis?
hypotensive
how is an allergy test performed?
skin pricks to break skin barrier, then add a drop of a specific antigen as well as a positive control (histamine) and a negative control, then wait for mast cells to act (10-15min)
