Understanding Pathophysiology
8th Edition
Author(s)Sue E. Huether
TEST BANK
Q1. A 6-year-old boy presents with recurrent bacterial
infections, delayed wound healing, and poor leukocyte
migration into infected tissues despite marked neutrophilia on
laboratory testing. Genetic analysis reveals defective β2-
integrin expression on leukocytes. The patient’s impaired host
defense is best explained by disruption of which cellular
process?
A. Ligand-gated ion channel activation
B. Cell-to-cell adhesion-mediated transmigration
,C. Passive membrane diffusion of cytokines
D. Mitochondrial oxidative phosphorylation
E. Ribosomal protein synthesis
Correct Answer: B
Rationale:
Clinical Clue:
Recurrent infections with inability of neutrophils to enter
tissues despite neutrophilia suggests defective leukocyte
adhesion.
Mechanism:
β2-integrins mediate leukocyte adhesion to endothelial cells
before transmigration into tissues.
Why the Correct Answer Is Right:
Leukocyte extravasation depends on cell adhesion molecules
that enable rolling, firm adhesion, and migration through
endothelium.
Why the Other Options Are Wrong:
A. Ion channels regulate membrane excitability, not leukocyte
migration.
C. Cytokines act through receptor-mediated signaling rather
than passive diffusion.
D. Oxidative phosphorylation defects cause energy failure, not
selective migration defects.
E. Ribosomal dysfunction would impair generalized protein
synthesis.
,Exam Trap (common misconception tested):
Confusing leukocytosis with effective immune function.
High-Yield Clinical Correlation:
Defects in adhesion molecules produce severe bacterial
infections with absent pus formation.
Q2. A patient with severe chronic alcoholism develops
confusion, cardiomyopathy, and lactic acidosis. Laboratory
evaluation demonstrates impaired pyruvate dehydrogenase
activity due to thiamine deficiency. The elevated lactate level
most directly results from failure of which cellular process?
A. Anaerobic glycolysis termination
B. Entry of pyruvate into the citric acid cycle
C. Fatty acid transport into lysosomes
D. Sodium-potassium ATPase activation
E. DNA replication during mitosis
Correct Answer: B
Rationale:
Clinical Clue:
Thiamine deficiency impairs pyruvate dehydrogenase activity.
Mechanism:
Pyruvate cannot be converted into acetyl-CoA, forcing
conversion to lactate.
, Why the Correct Answer Is Right:
Failure of pyruvate entry into the citric acid cycle shifts
metabolism toward anaerobic pathways and lactate
accumulation.
Why the Other Options Are Wrong:
A. Anaerobic glycolysis continues rather than terminates.
C. Fatty acid transport defects involve carnitine-related
disorders.
D. ATPase activity decreases secondary to ATP depletion.
E. DNA replication is unrelated to lactate production.
Exam Trap (common misconception tested):
Confusing glycolysis defects with defects in oxidative
metabolism.
High-Yield Clinical Correlation:
Thiamine deficiency particularly injures high-energy tissues
such as myocardium and nervous tissue.
Q3. A researcher exposes cultured hepatocytes to cyanide,
causing abrupt cessation of ATP generation despite adequate
oxygen delivery. Which intracellular structure is primarily
affected?
A. Rough endoplasmic reticulum
B. Golgi apparatus
C. Mitochondrial inner membrane
8th Edition
Author(s)Sue E. Huether
TEST BANK
Q1. A 6-year-old boy presents with recurrent bacterial
infections, delayed wound healing, and poor leukocyte
migration into infected tissues despite marked neutrophilia on
laboratory testing. Genetic analysis reveals defective β2-
integrin expression on leukocytes. The patient’s impaired host
defense is best explained by disruption of which cellular
process?
A. Ligand-gated ion channel activation
B. Cell-to-cell adhesion-mediated transmigration
,C. Passive membrane diffusion of cytokines
D. Mitochondrial oxidative phosphorylation
E. Ribosomal protein synthesis
Correct Answer: B
Rationale:
Clinical Clue:
Recurrent infections with inability of neutrophils to enter
tissues despite neutrophilia suggests defective leukocyte
adhesion.
Mechanism:
β2-integrins mediate leukocyte adhesion to endothelial cells
before transmigration into tissues.
Why the Correct Answer Is Right:
Leukocyte extravasation depends on cell adhesion molecules
that enable rolling, firm adhesion, and migration through
endothelium.
Why the Other Options Are Wrong:
A. Ion channels regulate membrane excitability, not leukocyte
migration.
C. Cytokines act through receptor-mediated signaling rather
than passive diffusion.
D. Oxidative phosphorylation defects cause energy failure, not
selective migration defects.
E. Ribosomal dysfunction would impair generalized protein
synthesis.
,Exam Trap (common misconception tested):
Confusing leukocytosis with effective immune function.
High-Yield Clinical Correlation:
Defects in adhesion molecules produce severe bacterial
infections with absent pus formation.
Q2. A patient with severe chronic alcoholism develops
confusion, cardiomyopathy, and lactic acidosis. Laboratory
evaluation demonstrates impaired pyruvate dehydrogenase
activity due to thiamine deficiency. The elevated lactate level
most directly results from failure of which cellular process?
A. Anaerobic glycolysis termination
B. Entry of pyruvate into the citric acid cycle
C. Fatty acid transport into lysosomes
D. Sodium-potassium ATPase activation
E. DNA replication during mitosis
Correct Answer: B
Rationale:
Clinical Clue:
Thiamine deficiency impairs pyruvate dehydrogenase activity.
Mechanism:
Pyruvate cannot be converted into acetyl-CoA, forcing
conversion to lactate.
, Why the Correct Answer Is Right:
Failure of pyruvate entry into the citric acid cycle shifts
metabolism toward anaerobic pathways and lactate
accumulation.
Why the Other Options Are Wrong:
A. Anaerobic glycolysis continues rather than terminates.
C. Fatty acid transport defects involve carnitine-related
disorders.
D. ATPase activity decreases secondary to ATP depletion.
E. DNA replication is unrelated to lactate production.
Exam Trap (common misconception tested):
Confusing glycolysis defects with defects in oxidative
metabolism.
High-Yield Clinical Correlation:
Thiamine deficiency particularly injures high-energy tissues
such as myocardium and nervous tissue.
Q3. A researcher exposes cultured hepatocytes to cyanide,
causing abrupt cessation of ATP generation despite adequate
oxygen delivery. Which intracellular structure is primarily
affected?
A. Rough endoplasmic reticulum
B. Golgi apparatus
C. Mitochondrial inner membrane
