NUR 5461/NUR5461 Module 3 V2 |
Pulmonary System Q&A with Rationale |
William Paterson University
1. Which type of alveolar cells is responsible for the production of surfactant?
A. Type I alveolar cells
B. Type II alveolar cells
C. Alveolar macrophages
D. Goblet cells
Correct Answer: B
Expert Explanation: Type II alveolar cells are specialized epithelial cells that secrete
pulmonary surfactant. This substance reduces surface tension at the air-liquid interface of
the alveoli, which prevents alveolar collapse at low lung volumes. Without adequate
surfactant, the work of breathing increases significantly and gas exchange is compromised.
2. A patient is diagnosed with pulmonary fibrosis. How does this condition typically affect
lung compliance?
A. Compliance is increased
B. Compliance is variable and follows atmospheric pressure
C. Compliance remains unchanged
D. Compliance is decreased
,Correct Answer: D
Expert Explanation: Pulmonary fibrosis involves the stiffening of lung tissue due to
excessive collagen deposition. This results in decreased lung compliance, meaning the
lungs become harder to inflate. Consequently, the patient must exert more effort to achieve
adequate ventilation during the respiratory cycle.
3. Which of the following describes the ‘shunting’ of blood in the pulmonary system?
A. Adequate ventilation but poor perfusion
B. Excessive ventilation and excessive perfusion
C. Poor ventilation but adequate perfusion
D. Adequate gas exchange in the dead space
Correct Answer: C
Expert Explanation: Shunting occurs when blood passes through the pulmonary
capillaries without participating in gas exchange due to unventilated alveoli. This leads to a
low Ventilation-Perfusion (V/Q) ratio and results in hypoxemia. Common causes include
atelectasis, pulmonary edema, or pneumonia where the alveoli are filled with fluid or
collapsed.
4. What is the primary stimulus for breathing in a healthy individual?
A. Low levels of oxygen in the blood
B. Low pH of the blood
, C. High levels of carbon dioxide in the blood
D. Expansion of the chest wall
Correct Answer: C
Expert Explanation: In healthy individuals, the central chemoreceptors in the medulla are
primarily sensitive to changes in PaCO2 and pH. An increase in carbon dioxide levels
(hypercapnia) triggers the respiratory center to increase the rate and depth of breathing.
This sensitive feedback loop ensures that CO2 levels remain within a narrow physiological
range.
5. A patient presents with a shift to the right in the oxyhemoglobin dissociation curve. Which
factor could cause this?
A. Hypothermia
B. Increased body temperature
C. Decreased 2,3-DPG
D. Alkalosis
Correct Answer: B
Expert Explanation: A shift to the right in the oxyhemoglobin dissociation curve indicates
a decreased affinity of hemoglobin for oxygen, facilitating oxygen unloading to the tissues.
Factors that cause this shift include increased temperature, increased PaCO2, and
decreased pH (acidosis). This is physiologically beneficial during periods of high metabolic
demand, such as exercise or fever.
Pulmonary System Q&A with Rationale |
William Paterson University
1. Which type of alveolar cells is responsible for the production of surfactant?
A. Type I alveolar cells
B. Type II alveolar cells
C. Alveolar macrophages
D. Goblet cells
Correct Answer: B
Expert Explanation: Type II alveolar cells are specialized epithelial cells that secrete
pulmonary surfactant. This substance reduces surface tension at the air-liquid interface of
the alveoli, which prevents alveolar collapse at low lung volumes. Without adequate
surfactant, the work of breathing increases significantly and gas exchange is compromised.
2. A patient is diagnosed with pulmonary fibrosis. How does this condition typically affect
lung compliance?
A. Compliance is increased
B. Compliance is variable and follows atmospheric pressure
C. Compliance remains unchanged
D. Compliance is decreased
,Correct Answer: D
Expert Explanation: Pulmonary fibrosis involves the stiffening of lung tissue due to
excessive collagen deposition. This results in decreased lung compliance, meaning the
lungs become harder to inflate. Consequently, the patient must exert more effort to achieve
adequate ventilation during the respiratory cycle.
3. Which of the following describes the ‘shunting’ of blood in the pulmonary system?
A. Adequate ventilation but poor perfusion
B. Excessive ventilation and excessive perfusion
C. Poor ventilation but adequate perfusion
D. Adequate gas exchange in the dead space
Correct Answer: C
Expert Explanation: Shunting occurs when blood passes through the pulmonary
capillaries without participating in gas exchange due to unventilated alveoli. This leads to a
low Ventilation-Perfusion (V/Q) ratio and results in hypoxemia. Common causes include
atelectasis, pulmonary edema, or pneumonia where the alveoli are filled with fluid or
collapsed.
4. What is the primary stimulus for breathing in a healthy individual?
A. Low levels of oxygen in the blood
B. Low pH of the blood
, C. High levels of carbon dioxide in the blood
D. Expansion of the chest wall
Correct Answer: C
Expert Explanation: In healthy individuals, the central chemoreceptors in the medulla are
primarily sensitive to changes in PaCO2 and pH. An increase in carbon dioxide levels
(hypercapnia) triggers the respiratory center to increase the rate and depth of breathing.
This sensitive feedback loop ensures that CO2 levels remain within a narrow physiological
range.
5. A patient presents with a shift to the right in the oxyhemoglobin dissociation curve. Which
factor could cause this?
A. Hypothermia
B. Increased body temperature
C. Decreased 2,3-DPG
D. Alkalosis
Correct Answer: B
Expert Explanation: A shift to the right in the oxyhemoglobin dissociation curve indicates
a decreased affinity of hemoglobin for oxygen, facilitating oxygen unloading to the tissues.
Factors that cause this shift include increased temperature, increased PaCO2, and
decreased pH (acidosis). This is physiologically beneficial during periods of high metabolic
demand, such as exercise or fever.
