HSC 4555 Exam 2 V2 | HSC 4555 Pathophysiology 1 | Actual Q&A with
Rationale (HSC4555 Exam 2) | University of Central Florida
1. Which cellular adaptation is characterized by a decrease in cell size, often resulting from
disuse or decreased hormonal stimulation?
A. Hypertrophy
B. Atrophy
C. Hyperplasia
D. Metaplasia
Answer: B
Explanation: Atrophy is a reduction in the size of cells, which leads to a reduction in the
size of the organ. This can occur due to decreased workload, loss of innervation, or
diminished blood supply. The cell functions at a lower level to survive under stressful
conditions.
2. In the context of cellular injury, what is the primary consequence of a failure of the
sodium-potassium (Na+/K+) pump due to ATP depletion?
A. Intracellular swelling
B. Increased protein synthesis
C. Cellular dehydration
D. Decreased osmotic pressure
Answer: A
Explanation: When ATP levels drop, the Na+/K+ pump fails, leading to an accumulation of
sodium inside the cell. This increase in intracellular sodium creates an osmotic gradient
that pulls water into the cell. Consequently, the cell swells, a condition known as oncosis or
vacuolar degeneration.
3. Which type of necrosis is typically associated with hypoxic injury in the brain?
A. Coagulative necrosis
B. Liquefactive necrosis
C. Caseous necrosis
D. Fat necrosis
Answer: B
,Explanation: Liquefactive necrosis occurs in the brain because brain cells are rich in
digestive hydrolytic enzymes and lipids. As cells die, these enzymes dissolve the tissue,
turning it into a soft, liquid mass. This process is distinct from coagulative necrosis seen in
most other organs.
4. A 55-year-old male with chronic gastroesophageal reflux disease (GERD) shows a change in
the epithelial lining of the esophagus from squamous to columnar cells. This is an example of:
A. Metaplasia
B. Hyperplasia
C. Dysplasia
D. Neoplasia
Answer: A
Explanation: Metaplasia is the reversible replacement of one mature cell type by another
mature cell type. In Barrett’s esophagus, the normal squamous epithelium is replaced by
columnar cells to better withstand acid stress. If the irritating stimulus is removed, the
tissue can revert to its original state.
5. Which mediator is primarily responsible for the rapid vasodilation and increased capillary
permeability seen in acute inflammation?
A. Histamine
B. Leukotrienes
C. Interleukin-1
D. Interferon
Answer: A
Explanation: Histamine is released by mast cells immediately following an injury or
immune trigger. It acts on H1 receptors to cause rapid contraction of endothelial cells and
widening of the gaps between them. This allows fluid and proteins to leak into the
interstitial space, causing redness and warmth.
6. The activation of the complement system via the classical pathway is initiated by:
A. Bacterial polysaccharides
B. Mannose-binding lectin
C. Endotoxins
D. Antigen-antibody complexes
Answer: D
, Explanation: The classical pathway of the complement system is triggered when C1 binds
to an antibody-antigen complex (IgG or IgM). This leads to a cascade of protein activations
that eventually results in the formation of the Membrane Attack Complex. Other pathways,
like the alternative pathway, are triggered by microbial surface components.
7. Which immunoglobulins are the first to be produced during a primary immune response?
A. IgG
B. IgA
C. IgE
D. IgM
Answer: D
Explanation: IgM is the largest immunoglobulin and the first one synthesized in response
to a new antigen. It is highly effective at agglutination due to its pentameric structure. IgG
eventually follows and provides long-term protection.
8. A patient experiences a severe allergic reaction to a bee sting. This type of hypersensitivity
is mediated by:
A. IgE antibodies
B. T-cytotoxic cells
C. Immune complexes
D. IgM antibodies
Answer: A
Explanation: Type I hypersensitivity is IgE-mediated and involves the degranulation of
mast cells upon subsequent exposure to an allergen. This leads to the release of histamine
and other inflammatory mediators. In severe cases, this can lead to systemic anaphylaxis
and airway compromise.
9. Which laboratory value is most indicative of the progression from HIV infection to AIDS?
A. CD4+ T-cell count below 200 cells/mm3
B. Increased viral load
C. Positive Western Blot test
D. Decreased B-cell production
Answer: A
Explanation: The clinical definition of AIDS includes a CD4+ T-lymphocyte count of less
than 200 cells/mm3 or the presence of an AIDS-defining opportunistic infection. HIV
Rationale (HSC4555 Exam 2) | University of Central Florida
1. Which cellular adaptation is characterized by a decrease in cell size, often resulting from
disuse or decreased hormonal stimulation?
A. Hypertrophy
B. Atrophy
C. Hyperplasia
D. Metaplasia
Answer: B
Explanation: Atrophy is a reduction in the size of cells, which leads to a reduction in the
size of the organ. This can occur due to decreased workload, loss of innervation, or
diminished blood supply. The cell functions at a lower level to survive under stressful
conditions.
2. In the context of cellular injury, what is the primary consequence of a failure of the
sodium-potassium (Na+/K+) pump due to ATP depletion?
A. Intracellular swelling
B. Increased protein synthesis
C. Cellular dehydration
D. Decreased osmotic pressure
Answer: A
Explanation: When ATP levels drop, the Na+/K+ pump fails, leading to an accumulation of
sodium inside the cell. This increase in intracellular sodium creates an osmotic gradient
that pulls water into the cell. Consequently, the cell swells, a condition known as oncosis or
vacuolar degeneration.
3. Which type of necrosis is typically associated with hypoxic injury in the brain?
A. Coagulative necrosis
B. Liquefactive necrosis
C. Caseous necrosis
D. Fat necrosis
Answer: B
,Explanation: Liquefactive necrosis occurs in the brain because brain cells are rich in
digestive hydrolytic enzymes and lipids. As cells die, these enzymes dissolve the tissue,
turning it into a soft, liquid mass. This process is distinct from coagulative necrosis seen in
most other organs.
4. A 55-year-old male with chronic gastroesophageal reflux disease (GERD) shows a change in
the epithelial lining of the esophagus from squamous to columnar cells. This is an example of:
A. Metaplasia
B. Hyperplasia
C. Dysplasia
D. Neoplasia
Answer: A
Explanation: Metaplasia is the reversible replacement of one mature cell type by another
mature cell type. In Barrett’s esophagus, the normal squamous epithelium is replaced by
columnar cells to better withstand acid stress. If the irritating stimulus is removed, the
tissue can revert to its original state.
5. Which mediator is primarily responsible for the rapid vasodilation and increased capillary
permeability seen in acute inflammation?
A. Histamine
B. Leukotrienes
C. Interleukin-1
D. Interferon
Answer: A
Explanation: Histamine is released by mast cells immediately following an injury or
immune trigger. It acts on H1 receptors to cause rapid contraction of endothelial cells and
widening of the gaps between them. This allows fluid and proteins to leak into the
interstitial space, causing redness and warmth.
6. The activation of the complement system via the classical pathway is initiated by:
A. Bacterial polysaccharides
B. Mannose-binding lectin
C. Endotoxins
D. Antigen-antibody complexes
Answer: D
, Explanation: The classical pathway of the complement system is triggered when C1 binds
to an antibody-antigen complex (IgG or IgM). This leads to a cascade of protein activations
that eventually results in the formation of the Membrane Attack Complex. Other pathways,
like the alternative pathway, are triggered by microbial surface components.
7. Which immunoglobulins are the first to be produced during a primary immune response?
A. IgG
B. IgA
C. IgE
D. IgM
Answer: D
Explanation: IgM is the largest immunoglobulin and the first one synthesized in response
to a new antigen. It is highly effective at agglutination due to its pentameric structure. IgG
eventually follows and provides long-term protection.
8. A patient experiences a severe allergic reaction to a bee sting. This type of hypersensitivity
is mediated by:
A. IgE antibodies
B. T-cytotoxic cells
C. Immune complexes
D. IgM antibodies
Answer: A
Explanation: Type I hypersensitivity is IgE-mediated and involves the degranulation of
mast cells upon subsequent exposure to an allergen. This leads to the release of histamine
and other inflammatory mediators. In severe cases, this can lead to systemic anaphylaxis
and airway compromise.
9. Which laboratory value is most indicative of the progression from HIV infection to AIDS?
A. CD4+ T-cell count below 200 cells/mm3
B. Increased viral load
C. Positive Western Blot test
D. Decreased B-cell production
Answer: A
Explanation: The clinical definition of AIDS includes a CD4+ T-lymphocyte count of less
than 200 cells/mm3 or the presence of an AIDS-defining opportunistic infection. HIV
