SCI 225 Pathophysiology
Complete Final Exam (Qns & Ans)
2025
Question 1
A 65‑year‑old patient presents in septic shock with hypotension
and tachycardia. Which mediator is most directly responsible for
the profound vasodilation observed in septic shock?
A. Interleukin‑1
B. Tumor necrosis factor‑α
C. Nitric oxide
D. Endothelin‑1
Correct ANS: C
Rationale: Nitric oxide (NO) plays a central role in septic
shock by causing intense vasodilation. Although cytokines such
©2025
,as TNF‑α and IL‑1 trigger NO production, it is the excessive NO
that leads to the drop in systemic vascular resistance.
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Question 2
A patient with acute myocardial ischemia develops significant
intracellular calcium overload. Which of the following events best
explains this phenomenon?
A. Failure of the Na⁺/K⁺‑ATPase pump leading to reversal of the
Na⁺/Ca²⁺ exchanger
B. Excessive activation of L‑type calcium channels due to
hyperkalemia
C. Direct damage to the sarcoplasmic reticulum releasing stored
calcium
D. Increased entry of calcium via voltage‑gated channels from
reperfusion
Correct ANS: A
Rationale: During ischemia, ATP depletion impairs the
Na⁺/K⁺‑ATPase pump, causing intracellular sodium accumulation.
This leads to a reversal of the Na⁺/Ca²⁺ exchanger, promoting
calcium influx and resulting in intracellular calcium overload—a
key contributor to cell injury.
©2025
,---
Question 3
In diabetic ketoacidosis, increased ketogenesis leads to metabolic
acidosis. Which enzyme catalyzes the rate‑limiting step in the
ketogenesis pathway?
A. Mitochondrial HMG‑CoA synthase
B. HMG‑CoA lyase
C. Acetoacetyl‑CoA thiolase
D. Pyruvate dehydrogenase
Correct ANS: A
Rationale: Mitochondrial HMG‑CoA synthase is the
rate‑limiting enzyme in ketogenesis, controlling the conversion of
acetyl‑CoA into HMG‑CoA and ultimately influencing ketone
body production.
---
Question 4
©2025
, A patient with chronic obstructive pulmonary disease (COPD)
exacerbation exhibits alveolar hyperinflation on imaging. What is
the primary pathophysiological mechanism underlying
emphysema in COPD?
A. Bronchospasm-induced airway narrowing
B. Protease‑antiprotease imbalance leading to alveolar wall
destruction
C. Mucus hypersecretion causing airway obstruction
D. Bronchoalveolar inflammatory cell infiltration with granuloma
formation
Correct ANS: B
Rationale: Emphysema results primarily from an imbalance
between proteases (such as neutrophil elastase) and antiproteases,
leading to the destruction of alveolar walls, loss of elastic recoil,
and subsequent alveolar hyperinflation.
---
Question 5
A 72‑year‑old patient with chronic heart failure exhibits
worsening fluid retention. Which neurohormonal factors are
chiefly responsible for this compensatory fluid retention?
A. Atrial natriuretic peptide (ANP) alone
©2025
Complete Final Exam (Qns & Ans)
2025
Question 1
A 65‑year‑old patient presents in septic shock with hypotension
and tachycardia. Which mediator is most directly responsible for
the profound vasodilation observed in septic shock?
A. Interleukin‑1
B. Tumor necrosis factor‑α
C. Nitric oxide
D. Endothelin‑1
Correct ANS: C
Rationale: Nitric oxide (NO) plays a central role in septic
shock by causing intense vasodilation. Although cytokines such
©2025
,as TNF‑α and IL‑1 trigger NO production, it is the excessive NO
that leads to the drop in systemic vascular resistance.
---
Question 2
A patient with acute myocardial ischemia develops significant
intracellular calcium overload. Which of the following events best
explains this phenomenon?
A. Failure of the Na⁺/K⁺‑ATPase pump leading to reversal of the
Na⁺/Ca²⁺ exchanger
B. Excessive activation of L‑type calcium channels due to
hyperkalemia
C. Direct damage to the sarcoplasmic reticulum releasing stored
calcium
D. Increased entry of calcium via voltage‑gated channels from
reperfusion
Correct ANS: A
Rationale: During ischemia, ATP depletion impairs the
Na⁺/K⁺‑ATPase pump, causing intracellular sodium accumulation.
This leads to a reversal of the Na⁺/Ca²⁺ exchanger, promoting
calcium influx and resulting in intracellular calcium overload—a
key contributor to cell injury.
©2025
,---
Question 3
In diabetic ketoacidosis, increased ketogenesis leads to metabolic
acidosis. Which enzyme catalyzes the rate‑limiting step in the
ketogenesis pathway?
A. Mitochondrial HMG‑CoA synthase
B. HMG‑CoA lyase
C. Acetoacetyl‑CoA thiolase
D. Pyruvate dehydrogenase
Correct ANS: A
Rationale: Mitochondrial HMG‑CoA synthase is the
rate‑limiting enzyme in ketogenesis, controlling the conversion of
acetyl‑CoA into HMG‑CoA and ultimately influencing ketone
body production.
---
Question 4
©2025
, A patient with chronic obstructive pulmonary disease (COPD)
exacerbation exhibits alveolar hyperinflation on imaging. What is
the primary pathophysiological mechanism underlying
emphysema in COPD?
A. Bronchospasm-induced airway narrowing
B. Protease‑antiprotease imbalance leading to alveolar wall
destruction
C. Mucus hypersecretion causing airway obstruction
D. Bronchoalveolar inflammatory cell infiltration with granuloma
formation
Correct ANS: B
Rationale: Emphysema results primarily from an imbalance
between proteases (such as neutrophil elastase) and antiproteases,
leading to the destruction of alveolar walls, loss of elastic recoil,
and subsequent alveolar hyperinflation.
---
Question 5
A 72‑year‑old patient with chronic heart failure exhibits
worsening fluid retention. Which neurohormonal factors are
chiefly responsible for this compensatory fluid retention?
A. Atrial natriuretic peptide (ANP) alone
©2025
