Q: Calculate the alveolar ventilation rate (AVR) for a patient with a tidal volume (TV) of 500 mL, dead space of 150 mL, and a respiratory rate of 12 breaths/min. Use the equation $$AVR = (TV - dead\ space) \times frequency.$$

$$AVR = (500 - 150) \times 12 = 4,200\ mL/min$$

Q: According to Dalton’s law, what is the partial pressure of oxygen ($$P_{O_2$}) at $$sea level if oxygen makes up 20.9% of atmospheric air and total atmospheric pressure is 760 mm Hg?

$$P_{O_2$} = 0.209 \times 760 = 159\ mm\ Hg$$

Question 1

Which of the following best describes the relationship between pressure and volume in the lungs according to Boyle’s Law?

Accepted Answer

Pressure and volume are inversely proportional; as volume increases, pressure decreases.

Question 2

A patient suffers a stab wound that punctures the parietal pleura. Which of the following is the most likely immediate consequence?

Accepted Answer

Intrapleural pressure becomes positive, leading to lung collapse (pneumothorax).

Question 3

Which equation correctly represents transpulmonary pressure?

Accepted Answer

$$P_{tp} = P_{pul} - P_{ip}$$

Question 4

During quiet expiration, which of the following events occurs?

Accepted Answer

Intrapulmonary pressure rises above atmospheric pressure, causing air to flow out.

Question 5

A premature infant is diagnosed with infant respiratory distress syndrome (IRDS). What is the primary physiological problem?

Accepted Answer

Insufficient surfactant production increases alveolar surface tension, causing alveolar collapse.

Question 6

Which of the following would most likely decrease lung compliance?

Accepted Answer

Development of nonelastic scar tissue (fibrosis) in the lungs.

Question 7

A patient with obstructive pulmonary disease is likely to have which of the following spirometry findings?

Accepted Answer

Increased total lung capacity (TLC) and residual volume (RV).

Question 8

Calculate the alveolar ventilation rate (AVR) for a patient with a tidal volume (TV) of 500 mL, dead space of 150 mL, and a respiratory rate of 12 breaths/min. Use the equation $$AVR = (TV - dead\ space) 	imes frequency.$$

Accepted Answer

$$AVR = (500 - 150) 	imes 12 = 4,200\ mL/min$$

Question 9

According to Dalton’s law, what is the partial pressure of oxygen ($$P_{O_2$}) at $$sea level if oxygen makes up 20.9% of atmospheric air and total atmospheric pressure is 760 mm Hg?

Accepted Answer

$$P_{O_2$} = 0.209 	imes 760 = 159\ mm\ Hg$$

Question 10

Which of the following best explains why CO2 diffuses in equal amounts with O2 across the respiratory membrane, despite a smaller partial pressure gradient?

Accepted Answer

CO2 is 20 times more soluble in plasma and alveolar fluid than O2.

Question 11

A patient with pneumonia develops pulmonary edema, increasing the thickness of the respiratory membrane. What is the most likely effect on gas exchange?

Accepted Answer

Oxygen diffusion into the blood decreases, leading to tissue hypoxia.

Question 12

Which of the following scenarios would result in a mismatch of ventilation and perfusion in the lungs?

Accepted Answer

A mucus plug blocks an alveolar duct, reducing ventilation but not perfusion.

Question 13

Which of the following is a correct calculation for vital capacity (VC)?

Accepted Answer

$$VC = TV + IRV + ERV$$

Question 14

A patient is breathing rapidly and shallowly. What is the most likely effect on their alveolar ventilation rate (AVR)?

Accepted Answer

AVR decreases because a greater proportion of each breath is dead space air.

Question 15

Which of the following best describes the effect of high alveolar CO2 on bronchiolar diameter?

Accepted Answer

Bronchioles dilate to allow more CO2 to be exhaled.

Question 16

Which of the following is NOT a factor that influences lung compliance?

Accepted Answer

Partial pressure of nitrogen in the alveoli

Question 17

A patient with emphysema has a reduced alveolar surface area. What is the most likely effect on external respiration?

Accepted Answer

Decreased rate of oxygen diffusion into the blood.

Question 18

Which of the following best describes the movement of oxygen and carbon dioxide during internal respiration?

Accepted Answer

Oxygen moves from blood to tissues; CO2 moves from tissues to blood.

Question 19

Which of the following is the best indicator of effective ventilation?

Accepted Answer

Alveolar ventilation rate (AVR)

Respiratory Physiology: Mechanics, Volumes, and Gas Exchange

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