| Adv Pathophysiology (2026) Q&A
1. Which two cell types are the primary mediators of the adaptive immune
response?
A) Neutrophils and macrophages
B) B lymphocytes and T lymphocytes
C) Mast cells and basophils
D) Natural killer cells and dendritic cells
Correct Answer: B lymphocytes and T lymphocytes
Rationale: The adaptive immune response is characterized by the activation of B
lymphocytes (humoral immunity) and T lymphocytes (cell-mediated immunity).
Neutrophils, macrophages, mast cells, basophils, natural killer cells, and dendritic
cells are primarily components of innate immunity or act as accessory cells.
2. What is the chief function of antibodies in host protection?
A) Directly lysing infected cells
B) Neutralizing bacterial toxins and blocking pathogen attachment
C) Activating phagocytosis by releasing histamine
D) Producing cytokines to stimulate T cells
Correct Answer: Neutralizing bacterial toxins and blocking pathogen
attachment
,Rationale: Antibodies protect the host primarily by neutralizing toxins, blocking
the attachment of pathogens to host cells, and opsonizing pathogens for
phagocytosis. They do not directly lyse cells, release histamine, or produce
cytokines.
3. What term describes the phagocyte function of adhering to capillary and venule
walls?
A) Diapedesis
B) Chemotaxis
C) Margination
D) Opsonization
Correct Answer: Margination
Rationale: Margination is the process by which phagocytes stick to the
endothelial lining of capillary and venule walls, a necessary step before diapedesis
(transmigration through the vessel wall). Chemotaxis is directed movement
toward a chemical signal, and opsonization enhances phagocytosis.
4. Which statement about allergens is correct?
A) Allergens are antigens that cause allergic responses.
B) Allergens are autoantibodies produced by the host.
C) Allergens are immunosuppressive cytokines.
D) Allergens are non-immunogenic substances.
Correct Answer: Allergens are antigens that cause allergic responses.
, Rationale: Allergens are environmental antigens (such as pollen, food proteins,
or drugs) that trigger an allergic (hypersensitivity) response in susceptible
individuals. They are not autoantibodies, immunosuppressive cytokines, or non-
immunogenic.
5. Which type of hypersensitivity reaction is the most common and is
characterized by an immediate response?
A) Type I
B) Type II
C) Type III
D) Type IV
Correct Answer: Type I
Rationale: Type I hypersensitivity, also known as immediate hypersensitivity, is
the most common type and includes allergic reactions such as anaphylaxis and hay
fever. It is mediated by IgE antibodies and occurs within minutes of exposure.
Types II, III, and IV have different mechanisms and timelines.
6. Which immunoglobulin class is primarily responsible for mediating Type I
hypersensitivity reactions?
A) IgA
B) IgG
C) IgM
D) IgE
Correct Answer: IgE