Q: If a patient’s tidal volume ($$V_T) is 500 mL$$, inspiratory reserve volume (IRV) is 3000 mL, expiratory reserve volume (ERV) is 1200 mL, and residual volume (RV) is 1200 mL, what is the patient’s vital capacity (VC)?

$$VC = V_T + IRV + ERV = 500 + 3000 + 1200 = 4700\ \text{mL}$$

Question 1

Which of the following best describes the primary function of surfactant in the alveoli?

Accepted Answer

It decreases surface tension, preventing alveolar collapse during exhalation.

Question 2

A patient with restrictive lung disease is most likely to have which of the following changes in lung compliance?

Accepted Answer

Decreased lung compliance

Question 3

During external inspiration, which process is responsible for the movement of air into the lungs?

Accepted Answer

Diffusion of gases from high to low pressure regions

Question 4

Which equation correctly represents Boyle's Law as it applies to the mechanics of breathing?

Accepted Answer

$$P_1V_1 = P_2V_2$$

Question 5

A person inhales deeply and then exhales as much air as possible. The volume of air exhaled is known as:

Accepted Answer

Vital capacity (VC)

Question 6

Which of the following statements about Dalton’s Law is correct?

Accepted Answer

The total pressure of a mixture of gases is equal to the sum of the partial pressures of each individual gas.

Question 7

Which lung volume is defined as the amount of air remaining in the lungs after a maximal exhalation?

Accepted Answer

Residual volume (RV)

Question 8

A patient is experiencing bronchoconstriction. Which of the following is most likely to occur?

Accepted Answer

Decreased airflow due to narrowed airways

Question 9

Which of the following best explains why respiratory flow occurs from the atmosphere into the lungs during inspiration?

Accepted Answer

Alveolar pressure becomes lower than atmospheric pressure.

Question 10

Which of the following is NOT a function of the respiratory system?

Accepted Answer

Production of red blood cells

Question 11

If a patient’s tidal volume ($$V_T) is 500 mL$$, inspiratory reserve volume (IRV) is 3000 mL, expiratory reserve volume (ERV) is 1200 mL, and residual volume (RV) is 1200 mL, what is the patient’s vital capacity (VC)?

Accepted Answer

$$VC = V_T + IRV + ERV = 500 + 3000 + 1200 = 4700\ 	ext{mL}$$

Question 12

Which of the following would most likely increase the anatomic dead space in the respiratory system?

Accepted Answer

Tracheal obstruction

Question 13

Which of the following best describes the relationship between lung compliance and elastance?

Accepted Answer

High compliance means the lungs easily expand, while high elastance means the lungs return to their original shape easily.

Question 14

During a respiratory cycle, which volume changes the most during normal quiet breathing?

Accepted Answer

Tidal volume ($$V_T)$$

Question 15

Which of the following scenarios best illustrates the application of Boyle’s Law in clinical practice?

Accepted Answer

A patient’s lung volume increases during inspiration, causing alveolar pressure to decrease and air to flow in.

Question 16

Which of the following is true regarding the movement of gases according to Dalton’s Law and Boyle’s Law?

Accepted Answer

Gases move from regions of higher pressure to lower pressure, and the total pressure is the sum of partial pressures.

Question 17

Which of the following would most likely decrease total pulmonary ventilation?

Accepted Answer

Decreased respiratory rate

Question 18

A patient with asthma experiences bronchoconstriction. Which of the following changes would you expect in their respiratory system?

Accepted Answer

Increased airway resistance and decreased airflow

Question 19

Which of the following best describes the function of alveolar type II cells?

Accepted Answer

They produce surfactant to reduce surface tension in the alveoli.

Question 20

Which of the following is most likely to occur if elastance of the lungs is abnormally high?

Accepted Answer

The lungs will be difficult to expand during inspiration.

Mechanics of Breathing: Key Concepts and Physiology

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