Understanding Pathophysiology
8th Edition
Author(s)Sue E. Huether
TEST BANK
Q1. A 6-year-old boy presents with recurrent respiratory
infections, chronic sinusitis, and situs inversus discovered
incidentally during imaging for pneumonia. Electron microscopy
of respiratory epithelial cells demonstrates absent dynein arms.
The impaired movement of which cellular structure most
directly explains this patient’s condition?
A. Intermediate filaments
B. Microtubules
C. Microfilaments
D. Tight junctions
E. Desmosomes
Correct Answer: B
,Rationale:
Clinical Clue:
Recurrent sinopulmonary infections with situs inversus suggests
defective ciliary motility.
Mechanism:
Ciliary movement depends on microtubules arranged in a 9+2
structure with dynein-mediated sliding.
Why the Correct Answer Is Right:
Microtubules form the structural backbone of motile cilia.
Dynein arm defects impair coordinated ciliary beating, reducing
mucociliary clearance and disrupting embryologic left-right
orientation.
Why the Other Options Are Wrong:
A. Intermediate filaments provide tensile strength but do not
generate ciliary motion.
C. Microfilaments are involved in cell contraction and motility,
not ciliary beating.
D. Tight junctions regulate paracellular permeability.
E. Desmosomes anchor adjacent cells against mechanical stress.
Exam Trap (common misconception tested):
Confusing actin-based microfilaments with microtubule-based
ciliary structures.
High-Yield Clinical Correlation:
Primary ciliary dyskinesia commonly presents with chronic
,respiratory disease and infertility due to impaired flagellar
movement.
Q2. A hospitalized patient develops severe generalized edema
after extensive thermal burns. Loss of which plasma membrane
function most directly contributes to the rapid shift of
intravascular fluid into the interstitial space?
A. Maintenance of selective permeability
B. Protein synthesis
C. Lysosomal digestion
D. DNA replication
E. ATP generation
Correct Answer: A
Rationale:
Clinical Clue:
Burn injury disrupts membrane integrity and causes capillary
leak.
Mechanism:
Cell membranes regulate movement of water and solutes
through selective permeability.
Why the Correct Answer Is Right:
Thermal injury damages membrane phospholipids and
membrane-associated proteins, increasing permeability and
allowing protein-rich fluid to escape into tissues.
, Why the Other Options Are Wrong:
B. Protein synthesis occurs primarily in ribosomes and rough
ER.
C. Lysosomal digestion relates to intracellular degradation.
D. DNA replication occurs in the nucleus.
E. ATP generation primarily occurs in mitochondria.
Exam Trap (common misconception tested):
Assuming edema is caused only by vascular injury rather than
altered membrane permeability.
High-Yield Clinical Correlation:
Loss of endothelial and cellular membrane integrity is central to
burn shock physiology.
Q3. A researcher exposes cultured cells to cyanide, leading to
abrupt cessation of oxidative phosphorylation. Within minutes,
the cells demonstrate swelling and membrane blebbing. The
earliest intracellular change most directly responsible for this
finding is failure of:
A. Ribosomal protein assembly
B. Sodium-potassium ATPase activity
C. Lysosomal enzyme degradation
D. DNA transcription
E. Golgi-mediated protein packaging
Correct Answer: B
Rationale:
8th Edition
Author(s)Sue E. Huether
TEST BANK
Q1. A 6-year-old boy presents with recurrent respiratory
infections, chronic sinusitis, and situs inversus discovered
incidentally during imaging for pneumonia. Electron microscopy
of respiratory epithelial cells demonstrates absent dynein arms.
The impaired movement of which cellular structure most
directly explains this patient’s condition?
A. Intermediate filaments
B. Microtubules
C. Microfilaments
D. Tight junctions
E. Desmosomes
Correct Answer: B
,Rationale:
Clinical Clue:
Recurrent sinopulmonary infections with situs inversus suggests
defective ciliary motility.
Mechanism:
Ciliary movement depends on microtubules arranged in a 9+2
structure with dynein-mediated sliding.
Why the Correct Answer Is Right:
Microtubules form the structural backbone of motile cilia.
Dynein arm defects impair coordinated ciliary beating, reducing
mucociliary clearance and disrupting embryologic left-right
orientation.
Why the Other Options Are Wrong:
A. Intermediate filaments provide tensile strength but do not
generate ciliary motion.
C. Microfilaments are involved in cell contraction and motility,
not ciliary beating.
D. Tight junctions regulate paracellular permeability.
E. Desmosomes anchor adjacent cells against mechanical stress.
Exam Trap (common misconception tested):
Confusing actin-based microfilaments with microtubule-based
ciliary structures.
High-Yield Clinical Correlation:
Primary ciliary dyskinesia commonly presents with chronic
,respiratory disease and infertility due to impaired flagellar
movement.
Q2. A hospitalized patient develops severe generalized edema
after extensive thermal burns. Loss of which plasma membrane
function most directly contributes to the rapid shift of
intravascular fluid into the interstitial space?
A. Maintenance of selective permeability
B. Protein synthesis
C. Lysosomal digestion
D. DNA replication
E. ATP generation
Correct Answer: A
Rationale:
Clinical Clue:
Burn injury disrupts membrane integrity and causes capillary
leak.
Mechanism:
Cell membranes regulate movement of water and solutes
through selective permeability.
Why the Correct Answer Is Right:
Thermal injury damages membrane phospholipids and
membrane-associated proteins, increasing permeability and
allowing protein-rich fluid to escape into tissues.
, Why the Other Options Are Wrong:
B. Protein synthesis occurs primarily in ribosomes and rough
ER.
C. Lysosomal digestion relates to intracellular degradation.
D. DNA replication occurs in the nucleus.
E. ATP generation primarily occurs in mitochondria.
Exam Trap (common misconception tested):
Assuming edema is caused only by vascular injury rather than
altered membrane permeability.
High-Yield Clinical Correlation:
Loss of endothelial and cellular membrane integrity is central to
burn shock physiology.
Q3. A researcher exposes cultured cells to cyanide, leading to
abrupt cessation of oxidative phosphorylation. Within minutes,
the cells demonstrate swelling and membrane blebbing. The
earliest intracellular change most directly responsible for this
finding is failure of:
A. Ribosomal protein assembly
B. Sodium-potassium ATPase activity
C. Lysosomal enzyme degradation
D. DNA transcription
E. Golgi-mediated protein packaging
Correct Answer: B
Rationale:
