Understanding Pathophysiology
8th Edition
Author(s)Sue E. Huether
TEST BANK
Q1. A 6-year-old boy is evaluated for recurrent bacterial
infections and delayed wound healing. Laboratory studies
demonstrate markedly impaired neutrophil migration despite
normal neutrophil counts. A defect in which cellular process
most directly explains this presentation?
A. Failure of cadherin-mediated intracellular anchoring
B. Impaired selectin-integrin adhesion signaling
C. Excessive gap junction conductivity
D. Reduced lysosomal enzyme synthesis
E. Defective mitochondrial oxidative phosphorylation
Correct Answer: B
Rationale:
,Clinical Clue:
Recurrent infections with impaired neutrophil migration
despite normal cell numbers indicates defective leukocyte
adhesion and transmigration.
Mechanism:
Neutrophil extravasation depends on selectin-mediated rolling
followed by integrin activation and firm endothelial adhesion.
Why the Correct Answer Is Right:
Integrin adhesion signaling defects impair leukocyte migration
into tissues, reducing effective inflammatory response despite
adequate circulating neutrophils.
Why the Other Options Are Wrong:
A. Cadherins primarily maintain stable tissue architecture
rather than leukocyte migration.
C. Gap junctions mediate intercellular ion exchange, not
leukocyte adhesion.
D. Lysosomal defects impair intracellular killing, not migration.
E. Mitochondrial dysfunction causes energy failure but does not
specifically explain adhesion defects.
Exam Trap (common misconception tested):
Confusing defective leukocyte migration with defective
phagocytosis.
High-Yield Clinical Correlation:
Leukocyte adhesion deficiency presents with recurrent
,bacterial infections, poor wound healing, and absent pus
formation.
Q2. A researcher exposes cultured hepatocytes to cyanide,
causing abrupt inhibition of cytochrome oxidase activity. Which
intracellular change would occur first?
A. Depletion of intracellular glycogen
B. Increased ribosomal protein synthesis
C. Failure of ATP-dependent sodium-potassium transport
D. Enhanced lysosomal autophagy
E. Increased DNA replication
Correct Answer: C
Rationale:
Clinical Clue:
Cyanide blocks oxidative phosphorylation by inhibiting the
electron transport chain.
Mechanism:
ATP depletion rapidly disables energy-dependent membrane
ion pumps.
Why the Correct Answer Is Right:
The sodium-potassium ATPase is highly ATP dependent; pump
failure causes intracellular sodium accumulation and cellular
swelling early in injury.
, Why the Other Options Are Wrong:
A. Glycogen depletion occurs later as anaerobic metabolism
continues.
B. Protein synthesis decreases during ATP depletion.
D. Autophagy may occur later during prolonged stress.
E. DNA replication requires adequate cellular energy.
Exam Trap (common misconception tested):
Assuming mitochondrial injury primarily affects nuclear
function first.
High-Yield Clinical Correlation:
Cellular swelling is one of the earliest reversible manifestations
of hypoxic injury.
Q3. A patient with severe gastroenteritis develops
hypokalemia. Muscle weakness results primarily from which
alteration in membrane physiology?
A. Persistent sodium channel activation
B. Reduced resting membrane potential excitability
C. Increased intracellular calcium influx
D. Enhanced chloride permeability
E. Accelerated ATP synthesis
Correct Answer: B
Rationale:
8th Edition
Author(s)Sue E. Huether
TEST BANK
Q1. A 6-year-old boy is evaluated for recurrent bacterial
infections and delayed wound healing. Laboratory studies
demonstrate markedly impaired neutrophil migration despite
normal neutrophil counts. A defect in which cellular process
most directly explains this presentation?
A. Failure of cadherin-mediated intracellular anchoring
B. Impaired selectin-integrin adhesion signaling
C. Excessive gap junction conductivity
D. Reduced lysosomal enzyme synthesis
E. Defective mitochondrial oxidative phosphorylation
Correct Answer: B
Rationale:
,Clinical Clue:
Recurrent infections with impaired neutrophil migration
despite normal cell numbers indicates defective leukocyte
adhesion and transmigration.
Mechanism:
Neutrophil extravasation depends on selectin-mediated rolling
followed by integrin activation and firm endothelial adhesion.
Why the Correct Answer Is Right:
Integrin adhesion signaling defects impair leukocyte migration
into tissues, reducing effective inflammatory response despite
adequate circulating neutrophils.
Why the Other Options Are Wrong:
A. Cadherins primarily maintain stable tissue architecture
rather than leukocyte migration.
C. Gap junctions mediate intercellular ion exchange, not
leukocyte adhesion.
D. Lysosomal defects impair intracellular killing, not migration.
E. Mitochondrial dysfunction causes energy failure but does not
specifically explain adhesion defects.
Exam Trap (common misconception tested):
Confusing defective leukocyte migration with defective
phagocytosis.
High-Yield Clinical Correlation:
Leukocyte adhesion deficiency presents with recurrent
,bacterial infections, poor wound healing, and absent pus
formation.
Q2. A researcher exposes cultured hepatocytes to cyanide,
causing abrupt inhibition of cytochrome oxidase activity. Which
intracellular change would occur first?
A. Depletion of intracellular glycogen
B. Increased ribosomal protein synthesis
C. Failure of ATP-dependent sodium-potassium transport
D. Enhanced lysosomal autophagy
E. Increased DNA replication
Correct Answer: C
Rationale:
Clinical Clue:
Cyanide blocks oxidative phosphorylation by inhibiting the
electron transport chain.
Mechanism:
ATP depletion rapidly disables energy-dependent membrane
ion pumps.
Why the Correct Answer Is Right:
The sodium-potassium ATPase is highly ATP dependent; pump
failure causes intracellular sodium accumulation and cellular
swelling early in injury.
, Why the Other Options Are Wrong:
A. Glycogen depletion occurs later as anaerobic metabolism
continues.
B. Protein synthesis decreases during ATP depletion.
D. Autophagy may occur later during prolonged stress.
E. DNA replication requires adequate cellular energy.
Exam Trap (common misconception tested):
Assuming mitochondrial injury primarily affects nuclear
function first.
High-Yield Clinical Correlation:
Cellular swelling is one of the earliest reversible manifestations
of hypoxic injury.
Q3. A patient with severe gastroenteritis develops
hypokalemia. Muscle weakness results primarily from which
alteration in membrane physiology?
A. Persistent sodium channel activation
B. Reduced resting membrane potential excitability
C. Increased intracellular calcium influx
D. Enhanced chloride permeability
E. Accelerated ATP synthesis
Correct Answer: B
Rationale:
