Question 1

A patient presents with a stab wound to the chest, resulting in the loss of the pressure gradient between the alveoli and the pleural cavity. Which of the following best describes the physiological consequence of this injury?

Accepted Answer

The lungs will collapse because intrapleural pressure equilibrates with alveolar pressure, eliminating the opposing force that keeps the lungs open.

Question 2

Which of the following equations correctly represents Boyle’s Law as it applies to pulmonary ventilation?

Accepted Answer

$$P V = 	ext{constant}$$

Question 3

A person is experiencing an asthma attack, leading to vigorous bronchoconstriction. Which of the following best explains the effect on airway resistance and ventilation?

Accepted Answer

Airway resistance increases, making it more difficult to ventilate the lungs.

Question 4

Which of the following best describes the role of surfactant in the alveoli?

Accepted Answer

It reduces surface tension, preventing alveolar collapse and making inflation easier.

Question 5

A patient with chronic obstructive pulmonary disease (COPD) has a reduced alveolar ventilation. Which of the following changes would you expect in their arterial blood gases?

Accepted Answer

Increased PCO2 and decreased pH (acidosis)

Question 6

Which of the following best explains why the right primary bronchus is more likely to be obstructed by a foreign object than the left?

Accepted Answer

The right bronchus is wider, shorter, and more vertical.

Question 7

A climber at high altitude develops increased respiratory rate and depth. Which of the following best describes the expected change in plasma pH and the underlying mechanism?

Accepted Answer

Plasma pH increases due to decreased CO2 (respiratory alkalosis).

Question 8

Which of the following formulas correctly calculates alveolar ventilation ($$V_A$$)?

Accepted Answer

$$V_A = f(V_T - V_D)$$

Question 9

A patient is hyperventilating due to anxiety. Which of the following best describes the expected changes in arterial blood gases?

Accepted Answer

Decreased PCO2 and increased pH (alkalosis)

Question 10

Which of the following best describes the effect of increased temperature and decreased pH on the oxygen-hemoglobin dissociation curve?

Accepted Answer

The curve shifts to the right, decreasing hemoglobin’s affinity for oxygen.

Question 11

Which of the following is the correct formula for calculating compliance ($$C_L) of $$the lung?

Accepted Answer

$$C_L = \frac{\Delta V_L}{\Delta P_L}$$

Question 12

A patient has a vital capacity (VC) of 4800 mL, an inspiratory reserve volume (IRV) of 3000 mL, and a tidal volume (TV) of 500 mL. What is their expiratory reserve volume (ERV)?

Accepted Answer

ERV = VC - (IRV + TV) = 4800 - (3000 + 500) = 1300 mL

Question 13

Which of the following best describes the Hering-Breuer reflex?

Accepted Answer

It is a stretch receptor reflex that prevents over-inflation of the lungs by terminating inspiration.

Question 14

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

Accepted Answer

Gas exchange between air and blood

Question 15

A patient with a thickened alveolar-capillary barrier is most likely to experience which of the following changes, according to Fick’s Law?

Accepted Answer

Decreased diffusion rate of gases

Question 16

Which of the following best describes the majority of carbon dioxide transport in the blood?

Accepted Answer

Converted to bicarbonate ion in plasma

Question 17

Which of the following best explains why CO2 diffuses more rapidly than O2 across the alveolar membrane?

Accepted Answer

CO2 is more soluble in plasma than O2.

Question 18

Which of the following is the correct formula for calculating minute ventilation ($$V_M$$)?

Accepted Answer

$$V_M = V_T 	imes f$$

Question 19

A patient is found to have a low ventilation/perfusion (Va/Q) ratio in a region of the lung. Which of the following best describes the expected changes in alveolar gas composition in that region?

Accepted Answer

Alveolar PO2 decreases and PCO2 increases

Question 20

Which of the following best describes the effect of parasympathetic stimulation on the bronchioles?

Accepted Answer

Bronchoconstriction

Respiratory System: Structure, Function, and Physiology

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