Understanding Pathophysiology
8th Edition
Author(s)Sue E. Huether
TEST BANK
Q1. A 6-year-old boy develops severe recurrent bacterial
infections and delayed wound healing. Flow cytometry
demonstrates markedly reduced expression of β2-integrins on
neutrophils. The inability of leukocytes to migrate effectively
into infected tissue is most directly explained by disruption of
which cellular process?
,A. Ligand-gated ion channel activation
B. Cell-to-cell adhesion between leukocytes and endothelium
C. Oxidative phosphorylation within neutrophil mitochondria
D. Endoplasmic reticulum protein synthesis
E. Lysosomal hydrolytic enzyme release
Correct Answer: B
Rationale:
Clinical Clue:
Recurrent bacterial infections with impaired leukocyte
migration suggests defective adhesion and transmigration.
Mechanism:
β2-integrins mediate firm adhesion of leukocytes to endothelial
cells before diapedesis.
Why the Correct Answer Is Right:
Leukocyte adhesion deficiency results from impaired integrin-
mediated cell adhesion, preventing migration into tissues
despite normal leukocyte production.
Why the Other Options Are Wrong:
A. Ion channels regulate signaling, not endothelial adhesion.
C. Neutrophils rely predominantly on glycolysis rather than
oxidative phosphorylation.
D. Protein synthesis defects would produce broader cellular
dysfunction.
E. Degranulation occurs after migration and activation.
,Exam Trap (common misconception tested):
Confusing leukocyte chemotaxis with endothelial adhesion.
High-Yield Clinical Correlation:
Integrin defects cause delayed umbilical cord separation,
neutrophilia, and absent pus formation.
Q2. A patient with chronic alcoholism develops confusion,
ophthalmoplegia, and ataxia. Cellular ATP production is
markedly impaired because of thiamine deficiency. Which
metabolic pathway is most directly disrupted first?
A. β-oxidation of fatty acids
B. Anaerobic glycolysis
C. Pentose phosphate pathway
D. Oxidative decarboxylation reactions in mitochondria
E. Cytosolic protein synthesis
Correct Answer: D
Rationale:
Clinical Clue:
Neurologic dysfunction in alcoholism strongly suggests
thiamine deficiency.
Mechanism:
Thiamine is a cofactor for pyruvate dehydrogenase and α-
ketoglutarate dehydrogenase in mitochondrial oxidative
metabolism.
, Why the Correct Answer Is Right:
Failure of oxidative decarboxylation limits acetyl-CoA formation
and ATP generation, particularly affecting high-energy tissues.
Why the Other Options Are Wrong:
A. Fatty acid oxidation is less immediately dependent on
thiamine.
B. Glycolysis itself does not require thiamine.
C. The pentose phosphate pathway primarily generates NADPH.
E. Protein synthesis impairment is secondary, not primary.
Exam Trap (common misconception tested):
Mistaking glycolysis as the primary ATP-limiting step in
thiamine deficiency.
High-Yield Clinical Correlation:
Wernicke encephalopathy reflects impaired cerebral energy
metabolism.
Q3. A laboratory study exposes skeletal muscle cells to a toxin
that irreversibly inhibits Na+/K+-ATPase activity. Which
immediate cellular change is most likely?
A. Increased intracellular potassium
B. Membrane hyperpolarization
C. Cellular swelling from osmotic water influx
D. Accelerated mitochondrial ATP production
E. Increased extracellular sodium concentration within the cell
Correct Answer: C
8th Edition
Author(s)Sue E. Huether
TEST BANK
Q1. A 6-year-old boy develops severe recurrent bacterial
infections and delayed wound healing. Flow cytometry
demonstrates markedly reduced expression of β2-integrins on
neutrophils. The inability of leukocytes to migrate effectively
into infected tissue is most directly explained by disruption of
which cellular process?
,A. Ligand-gated ion channel activation
B. Cell-to-cell adhesion between leukocytes and endothelium
C. Oxidative phosphorylation within neutrophil mitochondria
D. Endoplasmic reticulum protein synthesis
E. Lysosomal hydrolytic enzyme release
Correct Answer: B
Rationale:
Clinical Clue:
Recurrent bacterial infections with impaired leukocyte
migration suggests defective adhesion and transmigration.
Mechanism:
β2-integrins mediate firm adhesion of leukocytes to endothelial
cells before diapedesis.
Why the Correct Answer Is Right:
Leukocyte adhesion deficiency results from impaired integrin-
mediated cell adhesion, preventing migration into tissues
despite normal leukocyte production.
Why the Other Options Are Wrong:
A. Ion channels regulate signaling, not endothelial adhesion.
C. Neutrophils rely predominantly on glycolysis rather than
oxidative phosphorylation.
D. Protein synthesis defects would produce broader cellular
dysfunction.
E. Degranulation occurs after migration and activation.
,Exam Trap (common misconception tested):
Confusing leukocyte chemotaxis with endothelial adhesion.
High-Yield Clinical Correlation:
Integrin defects cause delayed umbilical cord separation,
neutrophilia, and absent pus formation.
Q2. A patient with chronic alcoholism develops confusion,
ophthalmoplegia, and ataxia. Cellular ATP production is
markedly impaired because of thiamine deficiency. Which
metabolic pathway is most directly disrupted first?
A. β-oxidation of fatty acids
B. Anaerobic glycolysis
C. Pentose phosphate pathway
D. Oxidative decarboxylation reactions in mitochondria
E. Cytosolic protein synthesis
Correct Answer: D
Rationale:
Clinical Clue:
Neurologic dysfunction in alcoholism strongly suggests
thiamine deficiency.
Mechanism:
Thiamine is a cofactor for pyruvate dehydrogenase and α-
ketoglutarate dehydrogenase in mitochondrial oxidative
metabolism.
, Why the Correct Answer Is Right:
Failure of oxidative decarboxylation limits acetyl-CoA formation
and ATP generation, particularly affecting high-energy tissues.
Why the Other Options Are Wrong:
A. Fatty acid oxidation is less immediately dependent on
thiamine.
B. Glycolysis itself does not require thiamine.
C. The pentose phosphate pathway primarily generates NADPH.
E. Protein synthesis impairment is secondary, not primary.
Exam Trap (common misconception tested):
Mistaking glycolysis as the primary ATP-limiting step in
thiamine deficiency.
High-Yield Clinical Correlation:
Wernicke encephalopathy reflects impaired cerebral energy
metabolism.
Q3. A laboratory study exposes skeletal muscle cells to a toxin
that irreversibly inhibits Na+/K+-ATPase activity. Which
immediate cellular change is most likely?
A. Increased intracellular potassium
B. Membrane hyperpolarization
C. Cellular swelling from osmotic water influx
D. Accelerated mitochondrial ATP production
E. Increased extracellular sodium concentration within the cell
Correct Answer: C
