Test Bank For Encyclopedia of Respiratory Medicine 2nd Edition.
Latest edition Editor: Sam Janes.Encyclopedia of Respiratory Medicine,
Second Edition, Six Volume Set
,Chapter 1. Scientific Basis of the Respiratory System Andrew Williams (UCL,
United Kingdom)
1. A 65-year-old man with a history of COPD presents with shortness of breath. Arterial blood
gas shows PaO₂ 58 mmHg and PaCO₂ 52 mmHg. Which process best explains his elevated CO₂
levels?
A. Increased alveolar surface area
B. Decreased alveolar ventilation
C. Increased pulmonary perfusion
D. Enhanced diffusion capacity
Answer: B. Decreased alveolar ventilation
Rationale: In COPD, airway obstruction reduces alveolar ventilation, leading to CO₂ retention
(hypercapnia). Alveolar hypoventilation decreases gas exchange efficiency. On a cellular level,
hypoventilation limits oxygen diffusion and CO₂ clearance due to reduced alveolar surface
exposure, altering the alveolar gas equation and increasing arterial CO₂.
2. A premature infant develops respiratory distress shortly after birth. The neonate likely has a
deficiency of which substance?
A. Elastin
B. Surfactant
C. Hemoglobin F
D. Collagen
Answer: B. Surfactant
Rationale: Surfactant, produced by type II alveolar cells, reduces surface tension and prevents
alveolar collapse (atelectasis). Deficiency leads to neonatal respiratory distress syndrome. At the
molecular level, surfactant phospholipids (mainly dipalmitoylphosphatidylcholine) stabilize
alveolar membranes during respiration.
3. A 40-year-old woman with interstitial lung disease presents with progressive dyspnea.
Pulmonary function tests show decreased lung compliance. Which structural change explains this
finding?
A. Destruction of alveolar walls
B. Fibrosis of alveolar interstitium
C. Increased surfactant production
D. Loss of pulmonary capillaries
Answer: B. Fibrosis of alveolar interstitium
Rationale: Fibrosis thickens alveolar walls, reducing compliance and making the lung stiffer.
The molecular basis involves fibroblast activation and collagen deposition, impairing elastic
recoil and gas diffusion.
4. During exercise, oxygen consumption increases. Which physiological mechanism primarily
maintains arterial oxygen levels?
A. Increased tidal volume and respiratory rate
B. Decreased cardiac output
,C. Reduced alveolar surface area
D. Vasoconstriction of pulmonary capillaries
Answer: A. Increased tidal volume and respiratory rate
Rationale: Exercise stimulates medullary respiratory centers, increasing ventilation to match
metabolic demand. Increased alveolar ventilation enhances oxygen diffusion and CO₂
elimination through improved gas gradients across alveolar membranes.
5. A 28-year-old patient is exposed to high altitude. Which adaptation helps maintain oxygen
delivery to tissues?
A. Decreased erythropoietin production
B. Increased alveolar CO₂
C. Increased red blood cell production
D. Reduced ventilation
Answer: C. Increased red blood cell production
Rationale: Hypoxia at high altitude stimulates renal erythropoietin (EPO) production, enhancing
erythropoiesis to improve oxygen transport. This adaptation compensates for reduced partial
pressure of oxygen by increasing hemoglobin content and oxygen-carrying capacity.
6. The diffusion of oxygen across the alveolar-capillary membrane is primarily influenced by:
A. Alveolar surface area and membrane thickness
B. Plasma protein levels
C. Systemic arterial pressure
D. Bronchial diameter
Answer: A. Alveolar surface area and membrane thickness
Rationale: Fick’s law states that diffusion rate is proportional to surface area and inversely
proportional to membrane thickness. Diseases like emphysema (↓ surface area) and fibrosis (↑
thickness) impair diffusion efficiency.
7. Which structure provides the greatest resistance to airflow in the normal respiratory system?
A. Trachea
B. Terminal bronchioles
C. Medium-sized bronchi
D. Alveolar ducts
Answer: C. Medium-sized bronchi
Rationale: Airway resistance is highest in medium bronchi due to turbulent airflow and smaller
cross-sectional area compared to distal bronchioles. Smooth muscle tone and mucosal edema
modulate resistance via neural and chemical control.
8. A patient with pneumonia shows localized alveolar consolidation. Which process is most
affected?
A. Oxygen diffusion
B. CO₂ binding to hemoglobin
C. Pulmonary perfusion
D. Surfactant synthesis
Answer: A. Oxygen diffusion
Rationale: Consolidation increases alveolar membrane thickness and fluid accumulation,
, reducing diffusion capacity. At the molecular level, impaired O₂ diffusion limits mitochondrial
oxidative phosphorylation, leading to hypoxemia.
9. The respiratory control centers are located in which part of the brain?
A. Cerebellum
B. Pons and medulla oblongata
C. Thalamus
D. Hypothalamus
Answer: B. Pons and medulla oblongata
Rationale: The medullary respiratory center regulates rhythmic breathing via the dorsal and
ventral respiratory groups. The pons modulates depth and rate of breathing through the
pneumotaxic and apneustic centers, integrating chemoreceptor feedback.
10. Which of the following best describes the role of surfactant proteins SP-A and SP-D?
A. Reduce alveolar surface tension
B. Enhance mucociliary clearance
C. Participate in innate immune defense
D. Transport oxygen across the alveolar membrane
Answer: C. Participate in innate immune defense
Rationale: SP-A and SP-D are collectins that bind pathogens, enhancing phagocytosis by
alveolar macrophages. This immune function complements the biophysical role of surfactant
phospholipids (SP-B, SP-C) in surface tension regulation.
11. A patient with pulmonary embolism has normal ventilation but impaired perfusion. This
represents which condition?
A. Low V/Q ratio
B. High V/Q ratio
C. Normal V/Q ratio
D. Shunt physiology
Answer: B. High V/Q ratio
Rationale: Ventilation–perfusion (V/Q) mismatch occurs when ventilation exceeds perfusion, as
seen in embolism. The result is dead space ventilation where alveoli receive air but lack blood
flow for gas exchange.
12. In chronic bronchitis, mucus hypersecretion is primarily due to hypertrophy of which cells?
A. Type I pneumocytes
B. Type II pneumocytes
C. Goblet cells
D. Endothelial cells
Answer: C. Goblet cells
Rationale: Chronic irritant exposure induces goblet cell hyperplasia and submucosal gland
hypertrophy, increasing mucus production. This obstructs airways and impairs mucociliary
clearance, predisposing to infection.
13. A 55-year-old smoker shows destruction of alveolar walls and enlarged air spaces. Which
enzyme imbalance contributes to this condition?
Latest edition Editor: Sam Janes.Encyclopedia of Respiratory Medicine,
Second Edition, Six Volume Set
,Chapter 1. Scientific Basis of the Respiratory System Andrew Williams (UCL,
United Kingdom)
1. A 65-year-old man with a history of COPD presents with shortness of breath. Arterial blood
gas shows PaO₂ 58 mmHg and PaCO₂ 52 mmHg. Which process best explains his elevated CO₂
levels?
A. Increased alveolar surface area
B. Decreased alveolar ventilation
C. Increased pulmonary perfusion
D. Enhanced diffusion capacity
Answer: B. Decreased alveolar ventilation
Rationale: In COPD, airway obstruction reduces alveolar ventilation, leading to CO₂ retention
(hypercapnia). Alveolar hypoventilation decreases gas exchange efficiency. On a cellular level,
hypoventilation limits oxygen diffusion and CO₂ clearance due to reduced alveolar surface
exposure, altering the alveolar gas equation and increasing arterial CO₂.
2. A premature infant develops respiratory distress shortly after birth. The neonate likely has a
deficiency of which substance?
A. Elastin
B. Surfactant
C. Hemoglobin F
D. Collagen
Answer: B. Surfactant
Rationale: Surfactant, produced by type II alveolar cells, reduces surface tension and prevents
alveolar collapse (atelectasis). Deficiency leads to neonatal respiratory distress syndrome. At the
molecular level, surfactant phospholipids (mainly dipalmitoylphosphatidylcholine) stabilize
alveolar membranes during respiration.
3. A 40-year-old woman with interstitial lung disease presents with progressive dyspnea.
Pulmonary function tests show decreased lung compliance. Which structural change explains this
finding?
A. Destruction of alveolar walls
B. Fibrosis of alveolar interstitium
C. Increased surfactant production
D. Loss of pulmonary capillaries
Answer: B. Fibrosis of alveolar interstitium
Rationale: Fibrosis thickens alveolar walls, reducing compliance and making the lung stiffer.
The molecular basis involves fibroblast activation and collagen deposition, impairing elastic
recoil and gas diffusion.
4. During exercise, oxygen consumption increases. Which physiological mechanism primarily
maintains arterial oxygen levels?
A. Increased tidal volume and respiratory rate
B. Decreased cardiac output
,C. Reduced alveolar surface area
D. Vasoconstriction of pulmonary capillaries
Answer: A. Increased tidal volume and respiratory rate
Rationale: Exercise stimulates medullary respiratory centers, increasing ventilation to match
metabolic demand. Increased alveolar ventilation enhances oxygen diffusion and CO₂
elimination through improved gas gradients across alveolar membranes.
5. A 28-year-old patient is exposed to high altitude. Which adaptation helps maintain oxygen
delivery to tissues?
A. Decreased erythropoietin production
B. Increased alveolar CO₂
C. Increased red blood cell production
D. Reduced ventilation
Answer: C. Increased red blood cell production
Rationale: Hypoxia at high altitude stimulates renal erythropoietin (EPO) production, enhancing
erythropoiesis to improve oxygen transport. This adaptation compensates for reduced partial
pressure of oxygen by increasing hemoglobin content and oxygen-carrying capacity.
6. The diffusion of oxygen across the alveolar-capillary membrane is primarily influenced by:
A. Alveolar surface area and membrane thickness
B. Plasma protein levels
C. Systemic arterial pressure
D. Bronchial diameter
Answer: A. Alveolar surface area and membrane thickness
Rationale: Fick’s law states that diffusion rate is proportional to surface area and inversely
proportional to membrane thickness. Diseases like emphysema (↓ surface area) and fibrosis (↑
thickness) impair diffusion efficiency.
7. Which structure provides the greatest resistance to airflow in the normal respiratory system?
A. Trachea
B. Terminal bronchioles
C. Medium-sized bronchi
D. Alveolar ducts
Answer: C. Medium-sized bronchi
Rationale: Airway resistance is highest in medium bronchi due to turbulent airflow and smaller
cross-sectional area compared to distal bronchioles. Smooth muscle tone and mucosal edema
modulate resistance via neural and chemical control.
8. A patient with pneumonia shows localized alveolar consolidation. Which process is most
affected?
A. Oxygen diffusion
B. CO₂ binding to hemoglobin
C. Pulmonary perfusion
D. Surfactant synthesis
Answer: A. Oxygen diffusion
Rationale: Consolidation increases alveolar membrane thickness and fluid accumulation,
, reducing diffusion capacity. At the molecular level, impaired O₂ diffusion limits mitochondrial
oxidative phosphorylation, leading to hypoxemia.
9. The respiratory control centers are located in which part of the brain?
A. Cerebellum
B. Pons and medulla oblongata
C. Thalamus
D. Hypothalamus
Answer: B. Pons and medulla oblongata
Rationale: The medullary respiratory center regulates rhythmic breathing via the dorsal and
ventral respiratory groups. The pons modulates depth and rate of breathing through the
pneumotaxic and apneustic centers, integrating chemoreceptor feedback.
10. Which of the following best describes the role of surfactant proteins SP-A and SP-D?
A. Reduce alveolar surface tension
B. Enhance mucociliary clearance
C. Participate in innate immune defense
D. Transport oxygen across the alveolar membrane
Answer: C. Participate in innate immune defense
Rationale: SP-A and SP-D are collectins that bind pathogens, enhancing phagocytosis by
alveolar macrophages. This immune function complements the biophysical role of surfactant
phospholipids (SP-B, SP-C) in surface tension regulation.
11. A patient with pulmonary embolism has normal ventilation but impaired perfusion. This
represents which condition?
A. Low V/Q ratio
B. High V/Q ratio
C. Normal V/Q ratio
D. Shunt physiology
Answer: B. High V/Q ratio
Rationale: Ventilation–perfusion (V/Q) mismatch occurs when ventilation exceeds perfusion, as
seen in embolism. The result is dead space ventilation where alveoli receive air but lack blood
flow for gas exchange.
12. In chronic bronchitis, mucus hypersecretion is primarily due to hypertrophy of which cells?
A. Type I pneumocytes
B. Type II pneumocytes
C. Goblet cells
D. Endothelial cells
Answer: C. Goblet cells
Rationale: Chronic irritant exposure induces goblet cell hyperplasia and submucosal gland
hypertrophy, increasing mucus production. This obstructs airways and impairs mucociliary
clearance, predisposing to infection.
13. A 55-year-old smoker shows destruction of alveolar walls and enlarged air spaces. Which
enzyme imbalance contributes to this condition?
