Understanding Pathophysiology
8th Edition
Author(s)Sue E. Huether
TEST BANK
Q1. A 6-year-old boy develops recurrent bacterial infections,
poor wound healing, and delayed separation of the umbilical
cord after birth. Neutrophil counts are markedly elevated, but
pus formation is minimal. Flow cytometry demonstrates absent
expression of β2-integrins on leukocytes. The defective cellular
process most directly explains failure of which event?
A. Generation of oxidative free radicals within phagolysosomes
B. Adhesion of leukocytes to vascular endothelium
C. Opsonization of bacteria by immunoglobulin G
,D. Chemotactic signaling mediated by interleukin-8
E. Bone marrow maturation of neutrophil precursors
Correct Answer: B
Rationale:
Clinical Clue:
Recurrent bacterial infections with impaired pus formation and
delayed umbilical cord separation strongly suggest leukocyte
adhesion deficiency.
Mechanism:
β2-integrins mediate firm leukocyte adhesion to endothelial
ICAM molecules during extravasation.
Why the Correct Answer Is Right:
Without integrin-mediated adhesion, neutrophils cannot exit
the bloodstream effectively, despite normal or elevated
circulating counts.
Why the Other Options Are Wrong:
A. Oxidative burst defects occur in chronic granulomatous
disease.
C. Opsonization defects are associated with antibody or
complement deficiencies.
D. Chemotaxis signaling may remain intact, but adhesion failure
prevents migration.
E. Neutrophil maturation is normal in leukocyte adhesion
deficiency.
,Exam Trap (common misconception tested):
Confusing leukocytosis with adequate immune function.
High-Yield Clinical Correlation:
Defects in adhesion molecules impair leukocyte margination
and transmigration despite preserved chemotactic stimuli.
Q2. A researcher exposes hepatocytes to cyanide, resulting in
rapid cessation of ATP production despite adequate oxygen
availability. Which cellular structure is primarily inhibited?
A. Lysosome
B. Smooth endoplasmic reticulum
C. Golgi apparatus
D. Mitochondrial inner membrane
E. Peroxisome
Correct Answer: D
Rationale:
Clinical Clue:
Cyanide poisoning prevents aerobic ATP generation despite
normal oxygen delivery.
Mechanism:
Cyanide inhibits cytochrome c oxidase within the electron
transport chain on the inner mitochondrial membrane.
, Why the Correct Answer Is Right:
Oxidative phosphorylation occurs across the mitochondrial
inner membrane, making it essential for ATP synthesis.
Why the Other Options Are Wrong:
A. Lysosomes digest cellular debris.
B. Smooth ER synthesizes lipids and detoxifies compounds.
C. Golgi apparatus modifies and packages proteins.
E. Peroxisomes metabolize very-long-chain fatty acids and
peroxide.
Exam Trap (common misconception tested):
Assuming ATP synthesis occurs diffusely throughout the
cytoplasm.
High-Yield Clinical Correlation:
Mitochondrial dysfunction causes energy failure in highly
metabolically active tissues such as brain and myocardium.
Q3. A woman with metastatic breast cancer develops severe
cachexia. Muscle biopsy demonstrates increased ubiquitin-
proteasome activity with accelerated degradation of
intracellular proteins. The affected pathway normally serves
which primary cellular function?
A. DNA replication fidelity
B. Intracellular protein quality control
C. Membrane phospholipid synthesis
8th Edition
Author(s)Sue E. Huether
TEST BANK
Q1. A 6-year-old boy develops recurrent bacterial infections,
poor wound healing, and delayed separation of the umbilical
cord after birth. Neutrophil counts are markedly elevated, but
pus formation is minimal. Flow cytometry demonstrates absent
expression of β2-integrins on leukocytes. The defective cellular
process most directly explains failure of which event?
A. Generation of oxidative free radicals within phagolysosomes
B. Adhesion of leukocytes to vascular endothelium
C. Opsonization of bacteria by immunoglobulin G
,D. Chemotactic signaling mediated by interleukin-8
E. Bone marrow maturation of neutrophil precursors
Correct Answer: B
Rationale:
Clinical Clue:
Recurrent bacterial infections with impaired pus formation and
delayed umbilical cord separation strongly suggest leukocyte
adhesion deficiency.
Mechanism:
β2-integrins mediate firm leukocyte adhesion to endothelial
ICAM molecules during extravasation.
Why the Correct Answer Is Right:
Without integrin-mediated adhesion, neutrophils cannot exit
the bloodstream effectively, despite normal or elevated
circulating counts.
Why the Other Options Are Wrong:
A. Oxidative burst defects occur in chronic granulomatous
disease.
C. Opsonization defects are associated with antibody or
complement deficiencies.
D. Chemotaxis signaling may remain intact, but adhesion failure
prevents migration.
E. Neutrophil maturation is normal in leukocyte adhesion
deficiency.
,Exam Trap (common misconception tested):
Confusing leukocytosis with adequate immune function.
High-Yield Clinical Correlation:
Defects in adhesion molecules impair leukocyte margination
and transmigration despite preserved chemotactic stimuli.
Q2. A researcher exposes hepatocytes to cyanide, resulting in
rapid cessation of ATP production despite adequate oxygen
availability. Which cellular structure is primarily inhibited?
A. Lysosome
B. Smooth endoplasmic reticulum
C. Golgi apparatus
D. Mitochondrial inner membrane
E. Peroxisome
Correct Answer: D
Rationale:
Clinical Clue:
Cyanide poisoning prevents aerobic ATP generation despite
normal oxygen delivery.
Mechanism:
Cyanide inhibits cytochrome c oxidase within the electron
transport chain on the inner mitochondrial membrane.
, Why the Correct Answer Is Right:
Oxidative phosphorylation occurs across the mitochondrial
inner membrane, making it essential for ATP synthesis.
Why the Other Options Are Wrong:
A. Lysosomes digest cellular debris.
B. Smooth ER synthesizes lipids and detoxifies compounds.
C. Golgi apparatus modifies and packages proteins.
E. Peroxisomes metabolize very-long-chain fatty acids and
peroxide.
Exam Trap (common misconception tested):
Assuming ATP synthesis occurs diffusely throughout the
cytoplasm.
High-Yield Clinical Correlation:
Mitochondrial dysfunction causes energy failure in highly
metabolically active tissues such as brain and myocardium.
Q3. A woman with metastatic breast cancer develops severe
cachexia. Muscle biopsy demonstrates increased ubiquitin-
proteasome activity with accelerated degradation of
intracellular proteins. The affected pathway normally serves
which primary cellular function?
A. DNA replication fidelity
B. Intracellular protein quality control
C. Membrane phospholipid synthesis
