Q: Calculate the vital capacity (VC) for a person with the following pulmonary volumes: tidal volume (TV) = 500 mL, inspiratory reserve volume (IRV) = 3000 mL, expiratory reserve volume (ERV) = 1200 mL.

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

Q: A person’s tidal volume is 500 mL, and they take 12 breaths per minute. What is their minute volume?

$$Minute\ Volume = TV \times \text{breaths per minute} = 500\ \text{mL} \times 12 = 6000\ \text{mL/min}$$

Question 1

According to Boyle’s law, what happens to the pressure of a gas if the volume of its container is doubled, assuming temperature and the number of gas molecules remain constant?

Accepted Answer

The pressure is halved.

Question 2

During inspiration, which of the following best describes the changes in intrapulmonary and atmospheric pressures that drive air into the lungs?

Accepted Answer

Intrapulmonary pressure falls below atmospheric pressure.

Question 3

Which of the following scenarios would most likely result in a collapsed lung (pneumothorax)?

Accepted Answer

Intrapleural pressure rises to equal or exceed atmospheric pressure.

Question 4

Which muscle is the primary driver of quiet inspiration, and what is its action?

Accepted Answer

Diaphragm; contracts and flattens, increasing thoracic cavity height.

Question 5

A patient is experiencing difficulty inflating their alveoli due to increased surface tension. Which substance is most likely deficient in this patient?

Accepted Answer

Surfactant

Question 6

Which of the following best explains why airway resistance decreases during inspiration?

Accepted Answer

Airways are pulled open as the lungs expand, increasing their diameter.

Question 7

Calculate the vital capacity (VC) for a person with the following pulmonary volumes: tidal volume (TV) = 500 mL, inspiratory reserve volume (IRV) = 3000 mL, expiratory reserve volume (ERV) = 1200 mL.

Accepted Answer

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

Question 8

Which of the following best describes the function of a yawn?

Accepted Answer

It takes lung volume to inspiratory capacity, minimizing alveolar collapse during sleep.

Question 9

A premature infant is diagnosed with respiratory distress syndrome (RDS). Which of the following best explains the underlying cause?

Accepted Answer

Insufficient surfactant production increases alveolar surface tension and decreases compliance.

Question 10

Which of the following would most likely increase pulmonary compliance?

Accepted Answer

Decreased alveolar surface tension due to increased surfactant.

Question 11

Which of the following formulas correctly calculates total lung capacity (TLC)?

Accepted Answer

$$TLC = IRV + TV + ERV + RV$$

Question 12

A person’s tidal volume is 500 mL, and they take 12 breaths per minute. What is their minute volume?

Accepted Answer

$$Minute\ Volume = TV 	imes 	ext{breaths per minute} = 500\ 	ext{mL} 	imes 12 = 6000\ 	ext{mL/min}$$

Question 13

Which of the following best describes the effect of bronchodilation on airflow?

Accepted Answer

Bronchodilation increases airway diameter, decreases resistance, and increases airflow.

Question 14

Which of the following is NOT a function of surfactant in the alveoli?

Accepted Answer

Increasing surface tension to promote alveolar collapse.

Question 15

Which of the following best explains why the lungs do not fully deflate during expiration?

Accepted Answer

The slight suction effect from intrapleural pressure and outward recoil of the chest wall oppose elastic recoil.

Question 16

A patient has a tidal volume (TV) of 500 mL, an anatomical dead space of 150 mL, and a respiratory rate of 14 breaths per minute. What is their alveolar ventilation rate (AVR)?

Accepted Answer

$$AVR = (TV - 	ext{dead space}) 	imes 	ext{respiratory rate} = (500\ 	ext{mL} - 150\ 	ext{mL}) 	imes 14 = 4900\ 	ext{mL/min}$$

Question 17

Which of the following best describes the role of the Heimlich maneuver in restoring breathing?

Accepted Answer

It delivers abdominal thrusts that forcefully decrease thoracic cavity size, increasing intrapulmonary pressure to expel an obstruction.

Question 18

Which of the following is the correct formula for calculating functional residual capacity (FRC)?

Accepted Answer

$$FRC = ERV + RV$$

Question 19

Which of the following best explains why a cough can cause soreness in abdominal and back muscles?

Accepted Answer

Forceful expiration uses accessory muscles of expiration, including abdominal and back muscles.

Pulmonary Ventilation: Mechanics, Physical Factors, and Pulmonary Volumes 21.3

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