NURS 231/NURS231 Module 4 V2 |
Pathophysiology Q&A with Rationale |
Portage Learning
1. Which process describes the movement of gases between the air in the alveoli and the
blood in the pulmonary capillaries?
A. Perfusion
B. Ventilation
C. Diffusion
D. Osmosis
Correct Answer: C
Rationale: Diffusion is the passive movement of oxygen and carbon dioxide across the
alveolar-capillary membrane based on partial pressure gradients. Ventilation refers strictly
to the movement of air into and out of the lungs, while perfusion refers to blood flow
through the pulmonary vasculature. This exchange is essential for maintaining arterial
blood gas levels within homeostatic limits.
2. A patient with chronic bronchitis typically presents with which of the following primary
pathophysiological changes?
A. Destruction of the alveolar walls and loss of elasticity
B. Reversible bronchospasms due to environmental triggers
,C. Infection and inflammation of the pleural cavity
D. Hypertrophy of mucus-secreting glands in the large airways
Correct Answer: D
Rationale: Chronic bronchitis is characterized by the hypersecretion of mucus and chronic
productive cough for at least 3 months in 2 consecutive years. The pathology involves
hypertrophy of the submucosal glands in the trachea and bronchi. This leads to airway
obstruction and an increased risk of respiratory infections compared to healthy
individuals.
3. Which of the following conditions is most likely to cause a ‘shift to the right’ in the
oxyhemoglobin dissociation curve?
A. Decreased body temperature (hypothermia)
B. Increased pH (alkalosis)
C. Decreased PCO2
D. Increased levels of 2,3-DPG
Correct Answer: D
Rationale: A shift to the right indicates a decreased affinity of hemoglobin for oxygen,
allowing for easier unloading at the tissue level. Factors that cause this shift include
increased CO2, increased temperature, decreased pH, and increased 2,3-DPG. This
mechanism ensures that metabolically active tissues receive more oxygen during periods of
high demand.
, 4. Type II alveolar cells are responsible for the production of which substance?
A. Elastin
B. Macrophage inflammatory protein
C. Hemoglobin
D. Surfactant
Correct Answer: D
Rationale: Type II alveolar cells secrete pulmonary surfactant, a lipoprotein that reduces
surface tension at the air-liquid interface of the alveoli. By reducing surface tension,
surfactant prevents alveolar collapse (atelectasis) during expiration. A deficiency in this
substance is the primary cause of respiratory distress syndrome in premature infants.
5. A tension pneumothorax is considered a medical emergency primarily because it causes:
A. A shift of the mediastinum and compression of the heart and great vessels
B. Rapid fluid accumulation in the pleural space
C. The rupture of small blebs on the visceral pleura
D. Chronic inflammation of the bronchial lining
Correct Answer: A
Rationale: In a tension pneumothorax, air enters the pleural space during inspiration but
cannot escape during expiration. The resulting increase in intrapleural pressure causes the
Pathophysiology Q&A with Rationale |
Portage Learning
1. Which process describes the movement of gases between the air in the alveoli and the
blood in the pulmonary capillaries?
A. Perfusion
B. Ventilation
C. Diffusion
D. Osmosis
Correct Answer: C
Rationale: Diffusion is the passive movement of oxygen and carbon dioxide across the
alveolar-capillary membrane based on partial pressure gradients. Ventilation refers strictly
to the movement of air into and out of the lungs, while perfusion refers to blood flow
through the pulmonary vasculature. This exchange is essential for maintaining arterial
blood gas levels within homeostatic limits.
2. A patient with chronic bronchitis typically presents with which of the following primary
pathophysiological changes?
A. Destruction of the alveolar walls and loss of elasticity
B. Reversible bronchospasms due to environmental triggers
,C. Infection and inflammation of the pleural cavity
D. Hypertrophy of mucus-secreting glands in the large airways
Correct Answer: D
Rationale: Chronic bronchitis is characterized by the hypersecretion of mucus and chronic
productive cough for at least 3 months in 2 consecutive years. The pathology involves
hypertrophy of the submucosal glands in the trachea and bronchi. This leads to airway
obstruction and an increased risk of respiratory infections compared to healthy
individuals.
3. Which of the following conditions is most likely to cause a ‘shift to the right’ in the
oxyhemoglobin dissociation curve?
A. Decreased body temperature (hypothermia)
B. Increased pH (alkalosis)
C. Decreased PCO2
D. Increased levels of 2,3-DPG
Correct Answer: D
Rationale: A shift to the right indicates a decreased affinity of hemoglobin for oxygen,
allowing for easier unloading at the tissue level. Factors that cause this shift include
increased CO2, increased temperature, decreased pH, and increased 2,3-DPG. This
mechanism ensures that metabolically active tissues receive more oxygen during periods of
high demand.
, 4. Type II alveolar cells are responsible for the production of which substance?
A. Elastin
B. Macrophage inflammatory protein
C. Hemoglobin
D. Surfactant
Correct Answer: D
Rationale: Type II alveolar cells secrete pulmonary surfactant, a lipoprotein that reduces
surface tension at the air-liquid interface of the alveoli. By reducing surface tension,
surfactant prevents alveolar collapse (atelectasis) during expiration. A deficiency in this
substance is the primary cause of respiratory distress syndrome in premature infants.
5. A tension pneumothorax is considered a medical emergency primarily because it causes:
A. A shift of the mediastinum and compression of the heart and great vessels
B. Rapid fluid accumulation in the pleural space
C. The rupture of small blebs on the visceral pleura
D. Chronic inflammation of the bronchial lining
Correct Answer: A
Rationale: In a tension pneumothorax, air enters the pleural space during inspiration but
cannot escape during expiration. The resulting increase in intrapleural pressure causes the
