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1. Which pathophysiologic mechanism best explains prolonged tissue hypoxia and
early reversible cellular injury?
A. lysosomal membrane rupture
B. nuclear fragmentation
C. irreversible plasma membrane disruption
D. ATP depletion
Answer: D. ATP depletion
Rationale: Hypoxia first reduces oxidative phosphorylation and ATP production. ATP-
dependent ion pumps then fail, causing cellular swelling before irreversible membrane and
nuclear injury occurs.
2. A patient is being evaluated for chronic systemic hypertension causing increased
left ventricular wall thickness. Which underlying process is most likely?
A. dysplasia
B. squamous metaplasia
C. myocyte hyperplasia
D. myocyte hypertrophy
Answer: D. myocyte hypertrophy
Rationale: Adult cardiac myocytes have little capacity for division, so chronic pressure
overload enlarges existing cells, producing hypertrophy.
3. Which physiologic change is most directly associated with controlled removal of
damaged cells without a major inflammatory response?
A. apoptosis
B. coagulative necrosis
C. liquefactive necrosis
D. gangrenous necrosis
Answer: A. apoptosis
Rationale: Apoptosis is programmed cell death with membrane integrity largely preserved
and cellular fragments removed without the marked inflammation typical of necrosis.
4. Which pathophysiologic mechanism best explains replacement of bronchial ciliated
columnar epithelium by stratified squamous epithelium in a smoker?
A. anaplasia
B. metaplasia
C. hyperplasia
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, D. hypertrophy
Answer: B. metaplasia
Rationale: Metaplasia is a reversible substitution of one mature cell type for another that
is more resistant to chronic stress.
5. A patient is being evaluated for generalized edema in severe hypoalbuminemia.
Which underlying process is most likely?
A. decreased capillary hydrostatic pressure
B. decreased plasma oncotic pressure
C. increased lymphatic drainage
D. increased plasma oncotic pressure
Answer: B. decreased plasma oncotic pressure
Rationale: Low serum albumin reduces the osmotic force that retains water in the vascular
space, promoting interstitial fluid accumulation.
6. Which physiologic change is most directly associated with neurologic deterioration
in severe acute hyponatremia?
A. increased serum osmolality
B. osmotic water movement out of neurons
C. water movement into brain cells causing cerebral edema
D. intracellular dehydration
Answer: C. water movement into brain cells causing cerebral edema
Rationale: Low extracellular sodium lowers serum osmolality, so water enters brain cells
and can cause cerebral edema, seizures, or herniation.
7. Which pathophysiologic mechanism best explains ECG changes associated with
clinically important hyperkalemia?
A. prominent U waves
B. diffuse ST elevation
C. tall peaked T waves
D. isolated prolonged QT interval
Answer: C. tall peaked T waves
Rationale: Hyperkalemia alters myocardial membrane depolarization and commonly
produces peaked T waves before more severe conduction abnormalities develop.
8. A patient is being evaluated for persistent vomiting with elevated serum
bicarbonate. Which underlying process is most likely?
A. respiratory acidosis with bicarbonate loss
B. metabolic acidosis with hyperventilation
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, C. metabolic alkalosis with compensatory hypoventilation
D. respiratory alkalosis with renal acid retention
Answer: C. metabolic alkalosis with compensatory hypoventilation
Rationale: Loss of gastric hydrogen ions produces metabolic alkalosis; respiratory
compensation retains carbon dioxide through hypoventilation.
9. Which physiologic change is most directly associated with diabetic ketoacidosis?
A. primary respiratory alkalosis
B. primary respiratory acidosis
C. normal-anion-gap metabolic alkalosis
D. high-anion-gap metabolic acidosis
Answer: D. high-anion-gap metabolic acidosis
Rationale: Accumulation of ketoacids consumes bicarbonate, producing a high-anion-gap
metabolic acidosis with compensatory hyperventilation.
10. Which pathophysiologic mechanism best explains activation of the renin-
angiotensin-aldosterone system after reduced renal perfusion?
A. reduced sympathetic activity
B. natriuresis and vasodilation
C. suppression of thirst and aldosterone
D. sodium retention and vasoconstriction
Answer: D. sodium retention and vasoconstriction
Rationale: Angiotensin II causes vasoconstriction and stimulates aldosterone, which
increases renal sodium and water retention.
11. A patient is being evaluated for first major leukocyte response in acute bacterial
inflammation. Which underlying process is most likely?
A. eosinophil predominance
B. basophil depletion
C. plasma-cell predominance
D. neutrophil recruitment
Answer: D. neutrophil recruitment
Rationale: Neutrophils are rapidly recruited to sites of acute bacterial infection where they
phagocytose organisms and damaged tissue.
12. Which physiologic change is most directly associated with histamine release
during an immediate inflammatory response?
A. inhibition of leukocyte migration
B. vasodilation and increased vascular permeability
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