Understanding Pathophysiology
8th Edition
Author(s)Sue E. Huether
TEST BANK
Q1. A 6-year-old boy presents with recurrent bacterial
infections, poor wound healing, and delayed separation of the
umbilical cord after birth. Laboratory studies demonstrate
markedly impaired neutrophil migration into infected tissues
despite normal neutrophil counts. Defective expression of
which cellular component most directly explains this
presentation?
A. Integrin-mediated adhesion molecules
B. Voltage-gated calcium channels
C. Mitochondrial ATP synthase complexes
D. Ribosomal peptidyl transferase enzymes
E. Nuclear histone deacetylases
,Correct Answer: A
Rationale:
Clinical Clue:
Delayed umbilical cord separation with recurrent infections
strongly suggests impaired leukocyte adhesion and migration.
Mechanism:
Integrins mediate firm leukocyte adhesion to endothelial
surfaces before transmigration into tissues.
Why the Correct Answer Is Right:
Defective integrin expression prevents neutrophils from
adhering to vascular endothelium and migrating toward sites of
infection, producing severe bacterial infections despite normal
circulating counts.
Why the Other Options Are Wrong:
B. Calcium channel dysfunction affects excitability rather than
leukocyte adhesion.
C. ATP synthase defects produce energy failure syndromes, not
isolated migration defects.
D. Ribosomal dysfunction impairs protein synthesis globally but
does not specifically impair transmigration.
E. Histone deacetylase abnormalities alter gene expression
broadly without this characteristic immunologic pattern.
Exam Trap (common misconception tested):
Normal leukocyte counts do not exclude severe defects in
leukocyte function.
,High-Yield Clinical Correlation:
Leukocyte adhesion defects produce neutrophilia because
neutrophils remain trapped within the circulation rather than
entering tissues.
Q2. A hepatocyte exposed to cyanide rapidly develops swelling,
membrane instability, and eventual lysis. The earliest
intracellular event precipitating this injury is most likely:
A. Activation of lysosomal hydrolases
B. Failure of oxidative phosphorylation
C. DNA fragmentation by endonucleases
D. Increased transcriptional activity
E. Excessive rough endoplasmic reticulum expansion
Correct Answer: B
Rationale:
Clinical Clue:
Cyanide poisoning rapidly impairs cellular oxygen utilization.
Mechanism:
Cyanide inhibits cytochrome oxidase within the electron
transport chain, halting ATP generation.
Why the Correct Answer Is Right:
ATP depletion disables energy-dependent membrane pumps,
especially Na+/K+-ATPase, leading to sodium and water influx
with cellular swelling.
, Why the Other Options Are Wrong:
A. Lysosomal rupture occurs later during irreversible injury.
C. DNA fragmentation is associated with apoptosis and later
injury stages.
D. ATP depletion suppresses rather than increases
transcription.
E. ER expansion is not the initiating event in hypoxic injury.
Exam Trap (common misconception tested):
Cell swelling occurs before membrane rupture and necrosis.
High-Yield Clinical Correlation:
Reversible hypoxic injury is characterized by ATP depletion,
membrane pump failure, and hydropic swelling.
Q3. A researcher studying epithelial barriers observes that
injected dye passes freely between adjacent intestinal epithelial
cells after selective disruption of a specific junctional complex.
Which structure was most likely disrupted?
A. Gap junction
B. Hemidesmosome
C. Tight junction
D. Focal adhesion
E. Intermediate filament anchor
Correct Answer: C
Rationale:
8th Edition
Author(s)Sue E. Huether
TEST BANK
Q1. A 6-year-old boy presents with recurrent bacterial
infections, poor wound healing, and delayed separation of the
umbilical cord after birth. Laboratory studies demonstrate
markedly impaired neutrophil migration into infected tissues
despite normal neutrophil counts. Defective expression of
which cellular component most directly explains this
presentation?
A. Integrin-mediated adhesion molecules
B. Voltage-gated calcium channels
C. Mitochondrial ATP synthase complexes
D. Ribosomal peptidyl transferase enzymes
E. Nuclear histone deacetylases
,Correct Answer: A
Rationale:
Clinical Clue:
Delayed umbilical cord separation with recurrent infections
strongly suggests impaired leukocyte adhesion and migration.
Mechanism:
Integrins mediate firm leukocyte adhesion to endothelial
surfaces before transmigration into tissues.
Why the Correct Answer Is Right:
Defective integrin expression prevents neutrophils from
adhering to vascular endothelium and migrating toward sites of
infection, producing severe bacterial infections despite normal
circulating counts.
Why the Other Options Are Wrong:
B. Calcium channel dysfunction affects excitability rather than
leukocyte adhesion.
C. ATP synthase defects produce energy failure syndromes, not
isolated migration defects.
D. Ribosomal dysfunction impairs protein synthesis globally but
does not specifically impair transmigration.
E. Histone deacetylase abnormalities alter gene expression
broadly without this characteristic immunologic pattern.
Exam Trap (common misconception tested):
Normal leukocyte counts do not exclude severe defects in
leukocyte function.
,High-Yield Clinical Correlation:
Leukocyte adhesion defects produce neutrophilia because
neutrophils remain trapped within the circulation rather than
entering tissues.
Q2. A hepatocyte exposed to cyanide rapidly develops swelling,
membrane instability, and eventual lysis. The earliest
intracellular event precipitating this injury is most likely:
A. Activation of lysosomal hydrolases
B. Failure of oxidative phosphorylation
C. DNA fragmentation by endonucleases
D. Increased transcriptional activity
E. Excessive rough endoplasmic reticulum expansion
Correct Answer: B
Rationale:
Clinical Clue:
Cyanide poisoning rapidly impairs cellular oxygen utilization.
Mechanism:
Cyanide inhibits cytochrome oxidase within the electron
transport chain, halting ATP generation.
Why the Correct Answer Is Right:
ATP depletion disables energy-dependent membrane pumps,
especially Na+/K+-ATPase, leading to sodium and water influx
with cellular swelling.
, Why the Other Options Are Wrong:
A. Lysosomal rupture occurs later during irreversible injury.
C. DNA fragmentation is associated with apoptosis and later
injury stages.
D. ATP depletion suppresses rather than increases
transcription.
E. ER expansion is not the initiating event in hypoxic injury.
Exam Trap (common misconception tested):
Cell swelling occurs before membrane rupture and necrosis.
High-Yield Clinical Correlation:
Reversible hypoxic injury is characterized by ATP depletion,
membrane pump failure, and hydropic swelling.
Q3. A researcher studying epithelial barriers observes that
injected dye passes freely between adjacent intestinal epithelial
cells after selective disruption of a specific junctional complex.
Which structure was most likely disrupted?
A. Gap junction
B. Hemidesmosome
C. Tight junction
D. Focal adhesion
E. Intermediate filament anchor
Correct Answer: C
Rationale:
