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39 Cards in this Set
- Front
- Back
What is Immunopathology?
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Immunopathology- the path of diseases associated with overreactivity or underreactivity of the immune system
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What is hypersensitivity?
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Allergy.
-Sometimes human body responds to antigens other than pathogenic microgrganisms- this is hypersensitivity- allergy |
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Fill in the blank
Antigens causing allergies are called ____ |
Allergens
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What are the two types of allergens?
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-Exogenous: pollen, mold, dust mites, cat and dog antigens, insect venom, etc.
-Endogenous: self-tissues (autoimmunities) - |
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True or False.
Allergies occur in persons who have been sensitized (previously exposed) to some allergen |
True
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Name the types of allergic reactions.
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-Type I
anaphylactic reactions (IgE) -Type II antibody mediated cell damage (IgG; IgM) -Type III immune complex -Type IV delayed hypersensitivity (T-cell) |
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Describe the portal of entry of allergens.
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- Epithelial portals of the respiratory tract, gastrointestinal tract and skin.
Note: The muscosal surfaces of the gut and respiratory system present a thin, moist surface that is normally quiet penetrable. |
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What are the mechanisms of type 1 Allergy.
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-Initial encounter with an allergen (sensitizing dose)
-Allegen is carried with lympathtics to lymph nodes- B nodes are activated and proliferate into plasma cells -IgE is produced – binds to the mast cells -Mast cells are located in the connective tissue throughout the body -No symptoms -The second contact with allergen -When the allergen encounters two adjacent antibody molecules already attached to the surface of the mast cell, it will bridge over two antibodies -This will trigger the mast cell to release mediators – (histamine, serotonin, leukotrien..) –degranulate causing allergy symptoms -Targets of the chemical mediators include: skin, upper respiratory tract, gastrointestinal tract, and conjunctiva -Symptoms include: rashes, itching, redness, rhinitis, sneezing, diarrhea, shedding of tears |
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Describe the second contact in type 1 allergy.
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-The second contact with allergen
-When the allergen encounters two adjacent antibody molecules already attached to the surface of the mast cell, it will bridge over two antibodies -This will trigger the mast cell to release mediators – (histamine, serotonin, leukotrien..) –degranulate causing allergy symptoms -Targets of the chemical mediators include: skin, upper respiratory tract, gastrointestinal tract, and conjunctiva -Symptoms include: rashes, itching, redness, rhinitis, sneezing, diarrhea, shedding of tears |
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What are the mediators that the mast cells release?
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This will trigger the mast cell to release mediators – (histamine, serotonin, leukotrien..) –degranulate causing allergy symptoms
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What is the fastest reacting mediator?
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Histamine
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What are the effects of histamine?
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Effects of histamine:
-Constrict smooth muscle of bronchi- labored breathing -Dilates blood vessels – hypotension, tachycardia, shock -Increases the permeability of blood vessels (swelling and redness), and mucus secretion(runny nose) |
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What are the two diseases associated with Type 1 Hypersensitivity?
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Hay fever- allergic rhinitis
-Reactions to inhaled polle, mold spores -Symptoms: nasal congestion, sneezing, coughing -Eczema : atopic dermatitis -Sensitization: ingestion, inhalation, skin contact -Symptoms: thickened skin, lesions |
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Describe food allergy.
- What is affected -mode of entry - Symptoms - Allergens |
-Mode of entry is intestinal
-Affected: skin, respiratory tract, gastrointestinal system -Symptoms: eczema, rhinitis, asthma, anaphylaxis -Food allergens: peanuts, fish, milk, shellfish… |
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Describe drug allergy.
-Allergens |
Drug Allergy
-Some drugs can cause allergic reactions in some individuals (5-10% of patients) -The drug allergens: antibiotics (penicillin) sulfa drugs, aspirin |
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Anaphylactic reactions can occur in which 2 ways?
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Systemic (antigen is injected)
-Dilation of peripheral blood vessels throughtout the body –drop of blood pressure- shock -Can be fatal within a few minutes -Allergy to penicillin Localized reaction (antigen is inhaled or ingested) -itchy, water eyes, sneezing, coughing -allergy to pollen, dust mites, mold spores, some food |
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What are the diagnostic tests for allergies?
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Diagnostic tests include:
-Measuring the blood levels of tryptase (an enzyme released by mast cells) -Differential blood cell count (increased levels of basophil and eosinophils- indicate allergy) -Measuring the quantity of IgE immunoglobulin in blood -Skin test – skin is injected with the pure allergen |
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What are ways to deal with anaphylactic reactions?
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-Avoid contact with sensitizing agent
-Desensitization therapy (series of increasing doses) -Carry at all times Epinephrine (adrenalin) –reverses the constriction of the airways -Treatment: -Drugs that block the actions of lymphocytes -Corticosteroids – prevent synthesis of IgE -Antihistamines |
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What are the treatments for anaphylactic reactions?
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-Treatment:
-Drugs that block the actions of lymphocytes -Corticosteroids – prevent synthesis of IgE -Antihistamines |
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How does desensitization work?
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How does it work?
-Theory: -The injected allergen causes IgG antibodies to be produced (instead of IgE), they bind to allergens -Allergens removed before they react with IgE |
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What is type 2 Hypersensitivity and when does it occur?
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Involves complement assisted destruction of cells
-Includes: ( occurs when) -Transfusion reactions -Some types of autoimmunity |
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What are the four blood groups?
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A
B AB O |
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What are blood groups based on?
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based on the antigens present on the surface of the red blood cells
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True or False.
Blood does not contain antibodies against “non-self” blood type. |
FALSE
Blood contains antibodies against “non-self” blood type -Example: Type A contains antibody against type B |
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Which blood group can be used as a universal donor?
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O can be sued as universal donor
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Which blood group is a universal recipient?
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AB type is universal recipient
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What happens when there is transfusion of the wrong blood type?
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-Transfusion of the wrong blood type results in destruction of red blood cells -systematic shock and failure of kidneys
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What is the Rh http://www.flashcardexchange.com/mycards/add/1259201factor?
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Rh factor is another antigen found on the red blood cells
-Present in 85% and absent in 15% of humans -Blood typing contains information on presence/absence of Rh factor (A+, B-) |
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What happens when the mother has Rh - and the unborn baby has Rh +?
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Hypersensitivity can occur when Rh- mother is sensitized with Rh + red blood cells of their unborn baby
-In the case of 2nd pregnancy this can cause hemolysis of red blood cells of the newborn- hemolytic disease -Can be prevented by passive immunization of a mother with antibodies against Rh factor- injected right after delivery |
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What is Type 3 Hypersensitivity?
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Type 3 involves the reaction of soluble antigen with antibody and deposition of the resulting complexeses in basemenrt membranes of epithelial tissues.
Causes immune complex reaction or disease. Two diseases: - Arthus reaction - Serum sickness |
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Type IV Hypersensitivity is also known as what?
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-Also known as delayed hypersensitivity (one to several days following the 2nd contact)
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Describe Type IV Hypersensitivity.
What is involved in it and in what circumstances does it occur? |
Also known as delayed hypersensitivity (one to several days following the 2nd contact)
-Involves T-cells -Include -Delayed allergic reactions to infectious agent -Contact dermatitis -Graft rejection |
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Describe the diagnostic technique for detecting tuberculosis.
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Infectious Allergy
-Tuberculin reaction- diagnostic technique for detection of tuberculosis -Tuberculin (extract of Mycobacterium tuberculosis) is injected intradermally -A person sensitized to tuberculosis will respond with a raised red bump |
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Autoimmune diseases fall under which types of allergy?
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Fall into category of type II or type III hypersensitivity
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what are autoimmune diseases and why do they occur?
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Autoimmune diseases
-Response of immune system against one’s own organs – involves autoantibodies and T cells -Can target several major organs (systemic) or only one organ |
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What is Rheumatoid arthritis?
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Autoimmune disease
Rheumatoid arthritis – IgM, IgG and complement are deposited in the joints -Damage to the cartilage in the joints- loss of functioning and mobility |
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What is Lupus?
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Most severe autoimmune disease
Production of antibodies against different organs (kidneys, bone marrow, skin, nervous system, joints…) -The etiology is unknown -Role of hormones – 90% of cases in women -Viral infection not excluded *characteristic rash across the face |
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What is Multiple sclerosis?
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Autoimmune disease
Neurological disease -T-cells and macrophages attack the myelin sheath of nerves -Progression slow -The most severe symptoms – paralysis -Etiology – may involve an infective agent |
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Why do immunodeficiency diseases occur?
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Immunodeficiency Diseases:
-Components of the immune responses are absent -Can be caused by inherited abnormalities -Infections (AIDS) -Chemotherapy -Radiation -Due to: -Lack of B and T-cells -Congenital absence of thymus -High susceptibility to microbial infections -Lack of antibody production |