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. Flow cytometry demonstrates
markedly reduced expression of β2-integrins on neutrophils.
The patient’s recurrent infections are most directly explained
by failure of which cellular process?
A. Oxidative phosphorylation within neutrophil mitochondria
B. Adhesion-dependent transmigration across vascular
endothelium
C. Antigen presentation through major histocompatibility
complexes
D. Lysosomal degradation of engulfed microorganisms
E. Clonal expansion of neutrophil precursors
Correct Answer: B
,Rationale:
Clinical Clue:
Delayed umbilical cord separation and recurrent bacterial
infections strongly suggest leukocyte adhesion deficiency.
Mechanism:
β2-integrins mediate firm adhesion of leukocytes to endothelial
surfaces before diapedesis into tissues.
Why the Correct Answer Is Right:
Without functional integrins, neutrophils cannot exit the
bloodstream efficiently, impairing tissue migration and
bacterial clearance.
Why the Other Options Are Wrong:
A. ATP production is not the primary defect.
C. Antigen presentation is mainly performed by macrophages
and dendritic cells.
D. Phagolysosome function is intact.
E. Bone marrow neutrophil production is usually normal or
increased.
Exam Trap (common misconception tested):
Confusing defective leukocyte migration with impaired
phagocytosis.
High-Yield Clinical Correlation:
Leukocyte adhesion defects produce neutrophilia because
neutrophils remain trapped in circulation.
,Q2. A researcher exposes cultured skeletal muscle cells to
cyanide, causing abrupt inhibition of cytochrome oxidase
activity. Which intracellular change most directly accounts for
the subsequent decline in cellular function?
A. Failure of ribosomal peptide elongation
B. Increased lysosomal membrane permeability
C. Depletion of ATP required for ion homeostasis
D. Excessive glycogen accumulation in the cytoplasm
E. Increased DNA transcription within the nucleus
Correct Answer: C
Rationale:
Clinical Clue:
Cyanide inhibits the electron transport chain.
Mechanism:
Blocking oxidative phosphorylation sharply reduces ATP
generation.
Why the Correct Answer Is Right:
ATP depletion impairs Na+/K+-ATPase activity, causing cellular
swelling, membrane dysfunction, and loss of electrochemical
gradients.
Why the Other Options Are Wrong:
A. Protein synthesis declines later secondary to energy failure.
B. Lysosomal rupture is a later event.
C. Glycogen is depleted, not accumulated.
E. Transcription decreases under severe hypoxia.
, Exam Trap (common misconception tested):
Assuming hypoxic injury initially damages DNA rather than
membrane ion regulation.
High-Yield Clinical Correlation:
ATP depletion is the earliest critical event in many forms of
reversible cellular injury.
Q3. A patient with severe hypoalbuminemia develops
generalized edema. At the cellular level, endothelial water
movement into the interstitium is best explained by disruption
of which membrane transport principle?
A. Facilitated diffusion down a concentration gradient
B. Secondary active transport coupled to sodium influx
C. Osmotically driven fluid movement across semipermeable
membranes
D. Vesicular transport mediated by clathrin-coated pits
E. ATP-independent ion exchange through gap junctions
Correct Answer: C
Rationale:
Clinical Clue:
Hypoalbuminemia lowers plasma oncotic pressure.
Mechanism:
Water shifts according to osmotic gradients across
semipermeable vascular membranes.
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. Flow cytometry demonstrates
markedly reduced expression of β2-integrins on neutrophils.
The patient’s recurrent infections are most directly explained
by failure of which cellular process?
A. Oxidative phosphorylation within neutrophil mitochondria
B. Adhesion-dependent transmigration across vascular
endothelium
C. Antigen presentation through major histocompatibility
complexes
D. Lysosomal degradation of engulfed microorganisms
E. Clonal expansion of neutrophil precursors
Correct Answer: B
,Rationale:
Clinical Clue:
Delayed umbilical cord separation and recurrent bacterial
infections strongly suggest leukocyte adhesion deficiency.
Mechanism:
β2-integrins mediate firm adhesion of leukocytes to endothelial
surfaces before diapedesis into tissues.
Why the Correct Answer Is Right:
Without functional integrins, neutrophils cannot exit the
bloodstream efficiently, impairing tissue migration and
bacterial clearance.
Why the Other Options Are Wrong:
A. ATP production is not the primary defect.
C. Antigen presentation is mainly performed by macrophages
and dendritic cells.
D. Phagolysosome function is intact.
E. Bone marrow neutrophil production is usually normal or
increased.
Exam Trap (common misconception tested):
Confusing defective leukocyte migration with impaired
phagocytosis.
High-Yield Clinical Correlation:
Leukocyte adhesion defects produce neutrophilia because
neutrophils remain trapped in circulation.
,Q2. A researcher exposes cultured skeletal muscle cells to
cyanide, causing abrupt inhibition of cytochrome oxidase
activity. Which intracellular change most directly accounts for
the subsequent decline in cellular function?
A. Failure of ribosomal peptide elongation
B. Increased lysosomal membrane permeability
C. Depletion of ATP required for ion homeostasis
D. Excessive glycogen accumulation in the cytoplasm
E. Increased DNA transcription within the nucleus
Correct Answer: C
Rationale:
Clinical Clue:
Cyanide inhibits the electron transport chain.
Mechanism:
Blocking oxidative phosphorylation sharply reduces ATP
generation.
Why the Correct Answer Is Right:
ATP depletion impairs Na+/K+-ATPase activity, causing cellular
swelling, membrane dysfunction, and loss of electrochemical
gradients.
Why the Other Options Are Wrong:
A. Protein synthesis declines later secondary to energy failure.
B. Lysosomal rupture is a later event.
C. Glycogen is depleted, not accumulated.
E. Transcription decreases under severe hypoxia.
, Exam Trap (common misconception tested):
Assuming hypoxic injury initially damages DNA rather than
membrane ion regulation.
High-Yield Clinical Correlation:
ATP depletion is the earliest critical event in many forms of
reversible cellular injury.
Q3. A patient with severe hypoalbuminemia develops
generalized edema. At the cellular level, endothelial water
movement into the interstitium is best explained by disruption
of which membrane transport principle?
A. Facilitated diffusion down a concentration gradient
B. Secondary active transport coupled to sodium influx
C. Osmotically driven fluid movement across semipermeable
membranes
D. Vesicular transport mediated by clathrin-coated pits
E. ATP-independent ion exchange through gap junctions
Correct Answer: C
Rationale:
Clinical Clue:
Hypoalbuminemia lowers plasma oncotic pressure.
Mechanism:
Water shifts according to osmotic gradients across
semipermeable vascular membranes.
