Understanding Pathophysiology
8th Edition
Author(s)Sue E. Huether
TEST BANK
Q1. A 4-year-old boy presents with recurrent bacterial
infections, delayed wound healing, and poor leukocyte
migration into infected tissue despite marked neutrophilia on
laboratory evaluation. Flow cytometry demonstrates absent
expression of β2-integrins on leukocytes. The impaired host
defense in this patient is most directly caused by failure of
which cellular process?
A. ATP-dependent lysosomal degradation
B. Cadherin-mediated epithelial attachment
C. Integrin-dependent transendothelial migration
,D. Gap junction propagation of intracellular calcium
E. Passive diffusion across phospholipid bilayers
Correct Answer: C
Rationale:
Clinical Clue:
Recurrent infections with neutrophilia but minimal pus
formation strongly suggests defective leukocyte adhesion and
migration.
Mechanism:
β2-integrins mediate firm leukocyte adhesion to endothelium
and subsequent diapedesis into tissues.
Why the Correct Answer Is Right:
Integrin-dependent transendothelial migration is essential for
neutrophil extravasation during inflammation. Loss of integrin
function prevents leukocytes from exiting circulation.
Why the Other Options Are Wrong:
A. Lysosomal degradation defects impair intracellular killing,
not migration.
B. Cadherins primarily mediate stable epithelial cell adhesion.
D. Gap junctions coordinate signaling between adjacent cells
but are unrelated to leukocyte trafficking.
E. Passive diffusion does not mediate cellular migration.
Exam Trap (common misconception tested):
Confusing selectin-mediated rolling with integrin-mediated firm
adhesion.
,High-Yield Clinical Correlation:
Leukocyte adhesion deficiency presents with recurrent
infections, delayed umbilical cord separation, and absent pus
formation.
Q2. A researcher exposes hepatocytes to cyanide, resulting in
rapid cessation of oxidative phosphorylation. Within minutes,
the cells develop swelling and loss of membrane potential. The
earliest mechanism responsible for cellular swelling is best
explained by failure of:
A. Ribosomal peptide elongation
B. Na+/K+-ATPase activity
C. Lysosomal protease activation
D. DNA replication checkpoint control
E. Golgi-mediated vesicular transport
Correct Answer: B
Rationale:
Clinical Clue:
Cyanide blocks oxidative phosphorylation, causing abrupt ATP
depletion.
Mechanism:
ATP depletion disables Na+/K+-ATPase pumps, allowing
intracellular sodium and water accumulation.
, Why the Correct Answer Is Right:
The Na+/K+-ATPase maintains osmotic balance. Failure causes
sodium retention and osmotic cellular swelling.
Why the Other Options Are Wrong:
A. Protein synthesis declines later and does not directly cause
swelling.
C. Lysosomal rupture is a later event in irreversible injury.
D. DNA checkpoints are unrelated to acute osmotic swelling.
E. Golgi transport failure does not produce immediate edema.
Exam Trap (common misconception tested):
Mistaking mitochondrial dysfunction itself for the direct cause
rather than ATP pump failure.
High-Yield Clinical Correlation:
Cellular swelling is a hallmark of reversible hypoxic injury.
Q3. A patient with chronic alcoholism develops severe muscle
weakness and cardiomyopathy due to thiamine deficiency.
Impaired function of which cellular structure most directly
explains decreased ATP generation in this condition?
A. Smooth endoplasmic reticulum
B. Peroxisomes
C. Mitochondria
D. Golgi apparatus
E. Nuclear envelope
Correct Answer: C
8th Edition
Author(s)Sue E. Huether
TEST BANK
Q1. A 4-year-old boy presents with recurrent bacterial
infections, delayed wound healing, and poor leukocyte
migration into infected tissue despite marked neutrophilia on
laboratory evaluation. Flow cytometry demonstrates absent
expression of β2-integrins on leukocytes. The impaired host
defense in this patient is most directly caused by failure of
which cellular process?
A. ATP-dependent lysosomal degradation
B. Cadherin-mediated epithelial attachment
C. Integrin-dependent transendothelial migration
,D. Gap junction propagation of intracellular calcium
E. Passive diffusion across phospholipid bilayers
Correct Answer: C
Rationale:
Clinical Clue:
Recurrent infections with neutrophilia but minimal pus
formation strongly suggests defective leukocyte adhesion and
migration.
Mechanism:
β2-integrins mediate firm leukocyte adhesion to endothelium
and subsequent diapedesis into tissues.
Why the Correct Answer Is Right:
Integrin-dependent transendothelial migration is essential for
neutrophil extravasation during inflammation. Loss of integrin
function prevents leukocytes from exiting circulation.
Why the Other Options Are Wrong:
A. Lysosomal degradation defects impair intracellular killing,
not migration.
B. Cadherins primarily mediate stable epithelial cell adhesion.
D. Gap junctions coordinate signaling between adjacent cells
but are unrelated to leukocyte trafficking.
E. Passive diffusion does not mediate cellular migration.
Exam Trap (common misconception tested):
Confusing selectin-mediated rolling with integrin-mediated firm
adhesion.
,High-Yield Clinical Correlation:
Leukocyte adhesion deficiency presents with recurrent
infections, delayed umbilical cord separation, and absent pus
formation.
Q2. A researcher exposes hepatocytes to cyanide, resulting in
rapid cessation of oxidative phosphorylation. Within minutes,
the cells develop swelling and loss of membrane potential. The
earliest mechanism responsible for cellular swelling is best
explained by failure of:
A. Ribosomal peptide elongation
B. Na+/K+-ATPase activity
C. Lysosomal protease activation
D. DNA replication checkpoint control
E. Golgi-mediated vesicular transport
Correct Answer: B
Rationale:
Clinical Clue:
Cyanide blocks oxidative phosphorylation, causing abrupt ATP
depletion.
Mechanism:
ATP depletion disables Na+/K+-ATPase pumps, allowing
intracellular sodium and water accumulation.
, Why the Correct Answer Is Right:
The Na+/K+-ATPase maintains osmotic balance. Failure causes
sodium retention and osmotic cellular swelling.
Why the Other Options Are Wrong:
A. Protein synthesis declines later and does not directly cause
swelling.
C. Lysosomal rupture is a later event in irreversible injury.
D. DNA checkpoints are unrelated to acute osmotic swelling.
E. Golgi transport failure does not produce immediate edema.
Exam Trap (common misconception tested):
Mistaking mitochondrial dysfunction itself for the direct cause
rather than ATP pump failure.
High-Yield Clinical Correlation:
Cellular swelling is a hallmark of reversible hypoxic injury.
Q3. A patient with chronic alcoholism develops severe muscle
weakness and cardiomyopathy due to thiamine deficiency.
Impaired function of which cellular structure most directly
explains decreased ATP generation in this condition?
A. Smooth endoplasmic reticulum
B. Peroxisomes
C. Mitochondria
D. Golgi apparatus
E. Nuclear envelope
Correct Answer: C
