PATHOPHYSIOLOGY MIDTERM EXAM
QUESTIONS & VERIFIED COMPLETE
ANSWERS
Hypersensitivity: Type 1 - correct answer ✔✔Type 1: Allergic reaction, Mediated by IgE,
Inflammation due to mast cell degranulation
Local symptoms:
-itching
-rash
Systemic symptoms:
-wheezing
Most dangerous = anaphylactic reaction
systemic response of hypotension, severe bronchoconstriction
Main treatment: epinephrine reverses the effects
Hypersensitivity: Type 2 - correct answer ✔✔Type 2: Cytotoxic reaction; tissue specific (ex:
thyroid tissue)
Macrophages are the primary effectors cells involved
Can cause tissue damage or alter function
Grave's disease (hyperthyroidism) - example of altering thyroid function, but does not destroy
thyroid tissue
,Incompatible blood type- example of cell/tissue damage that occurs; severe transfusion reaction
occurs and the transfused erythrocytes are destroyed by agglutination or complement-
mediated lysis.
Type 1 Hypersensitivity VS. Type 2 Hypersensitivity - correct answer ✔✔Type 1 Hypersensitivity
Organ Specific
Antibody binds to the antigen on the cell surface
Type 2 Hypersensitivity
Not Organ Specific
Antibody binds to the soluble antigen outside the cell surface that was released into the blood
or body fluids, and the complex is then deposited in the tissues
Hypersensitivity: Type 3 - Examples - correct answer ✔✔Rheumatoid arthritis:
Antigen/antibodies are deposited in the joints
Systemic Lupus Erythematosus (SLE)- very closely related to autoimmunity- antigen/antibodies
deposit in organs that cause tissue damage
Hypersensitivity: Type 4 - correct answer ✔✔Delayed response
Does not involve antigen/antibody complexes like Types 1, 2 and 3
Is T-cell mediated
, Differentiating Between the Rash of a Type 1 vs. Type 4 Reaction: - correct answer ✔✔Type 1:
Immediate hypersensitivity reactions, termed atopic dermatitis, are usually characterized by
widely distributed lesions
Type 4: Contact dermatitis (delayed hypersensitivity) consists of lesions only at the site of
contact with the allergen
The key determinant is the timing of the rash:
-Type 1 = Immediate
-Type 4 = Delayed: Several days following contact, ex would be poison ivy
Treatment of Type 4 Rash - correct answer ✔✔A non-severe case of contact dermatitis would
be treated with topical corticosteroid.
Why not epinephrine or antihistamines?
-Epinephrine is for emergent Type 1 anaphylactic reactions. Antihistamines act on the H1
receptors. Type 4 does not involve mast cells and H1 receptors.
Antibiotics not appropriate since not an infection
Autoimmunity - correct answer ✔✔Autoimmune disease can be familial, Affected family
members may not all develop the same disease, but several members may have different
disorders characterized by a variety of hypersensitivity reactions, These include autoimmune
and allergic reactions
Associations with particular autoimmune diseases have been identified for a variety of major
histocompatibility complex (MHC) alleles or non-MHC genes
Alloimmunity - correct answer ✔✔General term used to describe when an individual's immune
system reacts against antigens on the tissues of other members of the same species.