Understanding Pathophysiology
8th Edition
Author(s)Sue E. Huether
TEST BANK
Q1. A 6-year-old boy develops recurrent bacterial infections
and delayed wound healing. Neutrophils obtained from
peripheral blood demonstrate normal phagocytosis but fail to
migrate effectively toward inflammatory signals. A mutation
affecting actin filament reorganization is identified. The
impaired host defense most directly results from failure of
which cellular process?
A. Lysosomal enzyme activation
B. Chemotactic polarization and motility
C. Oxidative burst generation
,D. Fc receptor-mediated recognition
E. Complement protein synthesis
Correct Answer: B
Rationale:
Clinical Clue:
Recurrent infections with defective leukocyte migration despite
preserved phagocytosis indicates impaired cytoskeletal-
mediated chemotaxis.
Mechanism:
Actin cytoskeleton remodeling permits directional migration
toward chemoattractants through membrane protrusion and
cellular polarization.
Why the Correct Answer Is Right:
Chemotactic movement requires coordinated actin
polymerization and cytoskeletal reorganization. Defects impair
leukocyte extravasation and migration to infected tissues.
Why the Other Options Are Wrong:
A. Lysosomal activation occurs after phagosome formation and
is unrelated to migration defects.
C. Oxidative burst involves NADPH oxidase activity, not
cytoskeletal motility.
D. Fc receptor recognition mediates opsonization but not
locomotion.
E. Complement proteins are synthesized primarily in the liver.
,Exam Trap (common misconception tested):
Confusing impaired migration with impaired intracellular killing.
High-Yield Clinical Correlation:
Actin dysfunction can impair immune surveillance, wound
healing, and cellular division due to broad cytoskeletal
dependence.
Q2. A researcher inhibits Na+/K+-ATPase activity in cultured
myocardial cells. Within minutes, intracellular sodium
concentration rises. Which additional change is most likely to
occur?
A. Increased passive potassium influx
B. Reduced cellular osmotic swelling
C. Increased intracellular calcium accumulation
D. Hyperpolarization of the cell membrane
E. Increased ATP generation through oxidative phosphorylation
Correct Answer: C
Rationale:
Clinical Clue:
Na+/K+-ATPase inhibition disrupts ion gradients critical for
secondary transport systems.
Mechanism:
Elevated intracellular sodium decreases Na+/Ca2+ exchanger
, activity, reducing calcium extrusion and increasing intracellular
calcium.
Why the Correct Answer Is Right:
The Na+/Ca2+ exchanger depends on the sodium gradient
maintained by Na+/K+-ATPase. Loss of this gradient promotes
calcium accumulation.
Why the Other Options Are Wrong:
A. Potassium influx decreases because the gradient dissipates.
B. Sodium accumulation increases osmotic water entry and
swelling.
D. Membrane depolarization occurs rather than
hyperpolarization.
E. ATP generation falls because pump inhibition often reflects
ATP depletion or toxin exposure.
Exam Trap (common misconception tested):
Assuming Na+/K+-ATPase affects only sodium and potassium
rather than broader electrochemical coupling.
High-Yield Clinical Correlation:
Digitalis partially inhibits Na+/K+-ATPase to increase
intracellular calcium and myocardial contractility.
Q3. A patient with severe ischemia develops cellular swelling
and membrane blebbing in affected tissues. Electron
microscopy demonstrates dilated endoplasmic reticulum and
8th Edition
Author(s)Sue E. Huether
TEST BANK
Q1. A 6-year-old boy develops recurrent bacterial infections
and delayed wound healing. Neutrophils obtained from
peripheral blood demonstrate normal phagocytosis but fail to
migrate effectively toward inflammatory signals. A mutation
affecting actin filament reorganization is identified. The
impaired host defense most directly results from failure of
which cellular process?
A. Lysosomal enzyme activation
B. Chemotactic polarization and motility
C. Oxidative burst generation
,D. Fc receptor-mediated recognition
E. Complement protein synthesis
Correct Answer: B
Rationale:
Clinical Clue:
Recurrent infections with defective leukocyte migration despite
preserved phagocytosis indicates impaired cytoskeletal-
mediated chemotaxis.
Mechanism:
Actin cytoskeleton remodeling permits directional migration
toward chemoattractants through membrane protrusion and
cellular polarization.
Why the Correct Answer Is Right:
Chemotactic movement requires coordinated actin
polymerization and cytoskeletal reorganization. Defects impair
leukocyte extravasation and migration to infected tissues.
Why the Other Options Are Wrong:
A. Lysosomal activation occurs after phagosome formation and
is unrelated to migration defects.
C. Oxidative burst involves NADPH oxidase activity, not
cytoskeletal motility.
D. Fc receptor recognition mediates opsonization but not
locomotion.
E. Complement proteins are synthesized primarily in the liver.
,Exam Trap (common misconception tested):
Confusing impaired migration with impaired intracellular killing.
High-Yield Clinical Correlation:
Actin dysfunction can impair immune surveillance, wound
healing, and cellular division due to broad cytoskeletal
dependence.
Q2. A researcher inhibits Na+/K+-ATPase activity in cultured
myocardial cells. Within minutes, intracellular sodium
concentration rises. Which additional change is most likely to
occur?
A. Increased passive potassium influx
B. Reduced cellular osmotic swelling
C. Increased intracellular calcium accumulation
D. Hyperpolarization of the cell membrane
E. Increased ATP generation through oxidative phosphorylation
Correct Answer: C
Rationale:
Clinical Clue:
Na+/K+-ATPase inhibition disrupts ion gradients critical for
secondary transport systems.
Mechanism:
Elevated intracellular sodium decreases Na+/Ca2+ exchanger
, activity, reducing calcium extrusion and increasing intracellular
calcium.
Why the Correct Answer Is Right:
The Na+/Ca2+ exchanger depends on the sodium gradient
maintained by Na+/K+-ATPase. Loss of this gradient promotes
calcium accumulation.
Why the Other Options Are Wrong:
A. Potassium influx decreases because the gradient dissipates.
B. Sodium accumulation increases osmotic water entry and
swelling.
D. Membrane depolarization occurs rather than
hyperpolarization.
E. ATP generation falls because pump inhibition often reflects
ATP depletion or toxin exposure.
Exam Trap (common misconception tested):
Assuming Na+/K+-ATPase affects only sodium and potassium
rather than broader electrochemical coupling.
High-Yield Clinical Correlation:
Digitalis partially inhibits Na+/K+-ATPase to increase
intracellular calcium and myocardial contractility.
Q3. A patient with severe ischemia develops cellular swelling
and membrane blebbing in affected tissues. Electron
microscopy demonstrates dilated endoplasmic reticulum and
