Question 1

Which of the following best describes the relationship between pressure and volume in the lungs during pulmonary ventilation, 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 lung compliance ($$C_L) as $$described in the study materials?

Accepted Answer

$$C_L = \frac{\Delta V}{\Delta (P_{pul} - P_{ip})}$$

Question 4

A premature infant is diagnosed with Infant Respiratory Distress Syndrome (IRDS). What is the primary physiological problem in this condition?

Accepted Answer

Insufficient surfactant increases alveolar surface tension, leading to alveolar collapse.

Question 5

During a severe asthma attack, which of the following best explains why breathing becomes more difficult?

Accepted Answer

Airway resistance increases due to bronchiolar constriction.

Question 6

Which of the following scenarios would most likely decrease lung compliance?

Accepted Answer

Development of pulmonary fibrosis, replacing normal lung tissue with scar tissue.

Question 7

A patient is breathing pure oxygen at 2.5 atmospheres for an extended period. According to the study materials, what is a potential risk of this therapy?

Accepted Answer

Formation of harmful oxygen free radicals causing CNS disturbances.

Question 8

Which of the following best explains why resistance to airflow is usually insignificant in the respiratory tree?

Accepted Answer

The diameters of airways in the first part of the conducting zone are large and branching increases total cross-sectional area.

Question 9

Which of the following is the correct formula for calculating the flow of gas ($$F) in $$the airways?

Accepted Answer

$$F = \frac{\Delta P}{R}$$

Question 10

A patient with pneumonia develops thickened and edematous respiratory membranes. What is the most likely effect on gas exchange?

Accepted Answer

Gas exchange is impaired due to increased diffusion distance.

Question 11

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

Accepted Answer

It reduces alveolar surface tension, preventing alveolar collapse.

Question 12

Which combination of respiratory volumes equals vital capacity (VC)?

Accepted Answer

Tidal volume (TV) + Inspiratory reserve volume (IRV) + Expiratory reserve volume (ERV)

Question 13

Which of the following would most likely increase alveolar ventilation rate (AVR)?

Accepted Answer

Increasing tidal volume while keeping respiratory rate constant.

Question 14

During external respiration, which partial pressure gradient drives oxygen from the alveoli into the pulmonary capillaries?

Accepted Answer

Alveolar $$P_{O_2$} is $$higher than venous blood $$P_{O_2$}.$$

Question 15

Which of the following best explains why carbon dioxide diffuses in equal amounts with oxygen despite a smaller partial pressure gradient?

Accepted Answer

Carbon dioxide is 20 times more soluble in plasma and alveolar fluid than oxygen.

Question 16

A patient with emphysema has destruction of alveolar walls. What is the primary effect on gas exchange?

Accepted Answer

Decreased surface area for gas exchange, leading to impaired oxygenation.

Question 17

Which of the following is a direct result of a loss of negative intrapleural pressure?

Accepted Answer

Lung collapse (atelectasis)

Question 18

Which of the following best describes the effect of epinephrine during an acute asthma attack?

Accepted Answer

It dilates bronchioles, reducing airway resistance.

Question 19

Which of the following is the best explanation for why forced expiration is an active process?

Accepted Answer

It requires contraction of abdominal and internal intercostal muscles.

Question 20

A patient has a tidal volume (TV) of 500 mL, a respiratory rate of 12 breaths/min, and a dead space of 150 mL. What is their alveolar ventilation rate (AVR)?

Accepted Answer

$$AVR = (TV - dead\ space) 	imes respiratory\ rate = (500\ mL - 150\ mL) 	imes 12 = 4,200\ mL/min$$

Respiratory Physiology: Mechanics of Breathing and Pulmonary Ventilation

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