Question 1

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

Accepted Answer

It decreases the surface tension of alveolar fluid, reducing the energy required to expand the lungs.

Question 2

A patient suffers a puncture wound to the chest, allowing air into the pleural cavity. What is the most likely immediate consequence?

Accepted Answer

Atelectasis (lung collapse) due to loss of negative intrapleural pressure

Question 3

According to Boyle’s Law, what happens to the pressure in the lungs if the volume of the thoracic cavity increases during inspiration?

Accepted Answer

Pressure decreases, causing air to flow into the lungs.

Question 4

Which equation correctly represents the relationship between pressure and volume in the lungs during breathing?

Accepted Answer

$$P_1V_1 = P_2V_2$$

Question 5

Which of the following changes would shift the oxygen-hemoglobin dissociation curve to the right, promoting oxygen unloading at the tissues?

Accepted Answer

Increased H+ concentration (decreased pH)

Question 6

A person is experiencing an asthma attack. Which of the following best explains the physiological changes occurring in their airways?

Accepted Answer

Constriction of bronchioles and increased airway resistance

Question 7

Which of the following is the main form in which carbon dioxide is transported in the blood?

Accepted Answer

As bicarbonate ions ($$HCO_3$$^-$$) in plasma

Question 8

What is the effect of hyperventilation on blood pH, and why?

Accepted Answer

It increases blood pH by decreasing CO2 levels (hypocapnia).

Question 9

Which structure is responsible for closing off the larynx during swallowing to prevent food from entering the airway?

Accepted Answer

Epiglottis

Question 10

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

Accepted Answer

Decreased rate of diffusion of gases

Question 11

Which of the following best describes the Bohr effect?

Accepted Answer

A decrease in pH (increase in H+) causes hemoglobin to release more O2.

Question 12

Which of the following is true regarding the ventilation-perfusion coupling in the lungs?

Accepted Answer

High alveolar O2 causes dilation of pulmonary arterioles.

Question 13

Which of the following is a function of the nasal conchae?

Accepted Answer

They enhance air turbulence and help trap particles in mucus.

Question 14

A patient with chronic obstructive pulmonary disease (COPD) is likely to experience which of the following?

Accepted Answer

Decreased ability to force air out of the lungs

Question 15

Which of the following equations represents the relationship between flow, pressure, and resistance in the airways?

Accepted Answer

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

Question 16

Which of the following would most likely decrease lung compliance?

Accepted Answer

Nonelastic scar tissue (fibrosis) in the lungs

Question 17

Which of the following is the primary stimulus for increased breathing rate under normal conditions?

Accepted Answer

Increased arterial Pco2

Question 18

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 than O2.

Question 19

Which of the following is a consequence of rapid, shallow breathing on alveolar ventilation rate (AVR)?

Accepted Answer

AVR decreases because more air remains in the dead space.

Question 20

Which of the following is NOT a function of the nose?

Accepted Answer

Serving as the main site of gas exchange

The Respiratory System: Structure, Function, and Gas Exchange

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