Understanding Pathophysiology
8th Edition
Author(s)Sue E. Huether
TEST BANK
Q1. A 6-year-old boy develops recurrent bacterial respiratory
infections and chronic otitis media. Laboratory evaluation
demonstrates defective neutrophil migration despite normal
neutrophil counts. Flow cytometry reveals absence of β2-
integrins on leukocyte membranes. The impaired immune
response is most directly related to failure of which cellular
process?
A. ATP-dependent vesicular transport
B. Cell-to-cell adhesion signaling
C. Oxidative phosphorylation within mitochondria
,D. Lysosomal hydrolysis of bacterial proteins
E. DNA repair during mitosis
Correct Answer: B
Rationale:
Clinical Clue:
Recurrent infections with defective neutrophil migration
suggest leukocyte adhesion deficiency.
Mechanism:
β2-integrins mediate leukocyte adhesion to endothelial cells
during extravasation.
Why the Correct Answer Is Right:
Cell-to-cell adhesion molecules coordinate leukocyte
attachment, migration, and intercellular signaling required for
inflammatory responses.
Why the Other Options Are Wrong:
A. Vesicular transport does not explain impaired endothelial
attachment.
C. Mitochondrial dysfunction would produce systemic energy
failure.
D. Lysosomal defects impair intracellular killing, not migration.
E. DNA repair abnormalities cause genomic instability rather
than adhesion failure.
Exam Trap (common misconception tested):
Confusing defective leukocyte migration with impaired
phagocytic killing.
,High-Yield Clinical Correlation:
Integrin defects impair immune cell trafficking despite
preserved leukocyte production.
Q2. A researcher inhibits Na+/K+-ATPase activity in skeletal
muscle cells. Which physiologic change would most likely occur
first?
A. Increased intracellular potassium concentration
B. Hyperpolarization of the cell membrane
C. Cellular swelling from osmotic water influx
D. Enhanced calcium sequestration in the sarcoplasmic
reticulum
E. Increased mitochondrial ATP synthesis
Correct Answer: C
Rationale:
Clinical Clue:
Na+/K+-ATPase maintains ionic gradients and cellular osmotic
balance.
Mechanism:
Failure of active sodium extrusion causes intracellular sodium
accumulation, followed by osmotic water entry.
Why the Correct Answer Is Right:
Loss of membrane pump activity rapidly disrupts osmotic
homeostasis, leading to cellular swelling.
, Why the Other Options Are Wrong:
A. Intracellular potassium decreases, not increases.
B. Membrane depolarization occurs instead of
hyperpolarization.
D. Calcium handling becomes impaired.
E. ATP synthesis decreases because energy utilization and ionic
balance fail.
Exam Trap (common misconception tested):
Assuming membrane pumps primarily regulate electrical
activity rather than osmotic stability.
High-Yield Clinical Correlation:
Cellular swelling is an early reversible manifestation of ATP
depletion.
Q3. A patient with chronic alcohol use develops hepatocellular
injury characterized by accumulation of intracellular fat
droplets. The metabolic alteration most directly responsible
involves impaired:
A. Anaerobic glycolysis
B. Ribosomal protein synthesis
C. Lipid export and mitochondrial oxidation
D. DNA replication during S phase
E. Lysosomal membrane permeability
Correct Answer: C
Rationale:
8th Edition
Author(s)Sue E. Huether
TEST BANK
Q1. A 6-year-old boy develops recurrent bacterial respiratory
infections and chronic otitis media. Laboratory evaluation
demonstrates defective neutrophil migration despite normal
neutrophil counts. Flow cytometry reveals absence of β2-
integrins on leukocyte membranes. The impaired immune
response is most directly related to failure of which cellular
process?
A. ATP-dependent vesicular transport
B. Cell-to-cell adhesion signaling
C. Oxidative phosphorylation within mitochondria
,D. Lysosomal hydrolysis of bacterial proteins
E. DNA repair during mitosis
Correct Answer: B
Rationale:
Clinical Clue:
Recurrent infections with defective neutrophil migration
suggest leukocyte adhesion deficiency.
Mechanism:
β2-integrins mediate leukocyte adhesion to endothelial cells
during extravasation.
Why the Correct Answer Is Right:
Cell-to-cell adhesion molecules coordinate leukocyte
attachment, migration, and intercellular signaling required for
inflammatory responses.
Why the Other Options Are Wrong:
A. Vesicular transport does not explain impaired endothelial
attachment.
C. Mitochondrial dysfunction would produce systemic energy
failure.
D. Lysosomal defects impair intracellular killing, not migration.
E. DNA repair abnormalities cause genomic instability rather
than adhesion failure.
Exam Trap (common misconception tested):
Confusing defective leukocyte migration with impaired
phagocytic killing.
,High-Yield Clinical Correlation:
Integrin defects impair immune cell trafficking despite
preserved leukocyte production.
Q2. A researcher inhibits Na+/K+-ATPase activity in skeletal
muscle cells. Which physiologic change would most likely occur
first?
A. Increased intracellular potassium concentration
B. Hyperpolarization of the cell membrane
C. Cellular swelling from osmotic water influx
D. Enhanced calcium sequestration in the sarcoplasmic
reticulum
E. Increased mitochondrial ATP synthesis
Correct Answer: C
Rationale:
Clinical Clue:
Na+/K+-ATPase maintains ionic gradients and cellular osmotic
balance.
Mechanism:
Failure of active sodium extrusion causes intracellular sodium
accumulation, followed by osmotic water entry.
Why the Correct Answer Is Right:
Loss of membrane pump activity rapidly disrupts osmotic
homeostasis, leading to cellular swelling.
, Why the Other Options Are Wrong:
A. Intracellular potassium decreases, not increases.
B. Membrane depolarization occurs instead of
hyperpolarization.
D. Calcium handling becomes impaired.
E. ATP synthesis decreases because energy utilization and ionic
balance fail.
Exam Trap (common misconception tested):
Assuming membrane pumps primarily regulate electrical
activity rather than osmotic stability.
High-Yield Clinical Correlation:
Cellular swelling is an early reversible manifestation of ATP
depletion.
Q3. A patient with chronic alcohol use develops hepatocellular
injury characterized by accumulation of intracellular fat
droplets. The metabolic alteration most directly responsible
involves impaired:
A. Anaerobic glycolysis
B. Ribosomal protein synthesis
C. Lipid export and mitochondrial oxidation
D. DNA replication during S phase
E. Lysosomal membrane permeability
Correct Answer: C
Rationale:
