Q: Calculate the alveolar ventilation for a person with a tidal volume ($$V_T) of 600 mL$$, a respiratory rate (RR) of 10 breaths/min, and an anatomical dead space (DSV) of 150 mL. Use the formula: $$Alveolar\ Ventilation = (V_T \times RR) - (DSV \times RR).$$

$$Alveolar\ Ventilation = (600 \times 10) - (150 \times 10) = 6000 - 1500 = 4500\ mL/min$$

Question 1

Which of the following best describes the primary function of the respiratory zone in the lungs?

Accepted Answer

Exchange of gases between air and blood via diffusion

Question 2

A patient with pulmonary fibrosis has difficulty expanding their lungs. Which of the following best explains the physiological change in their lung compliance?

Accepted Answer

Fibrous scar tissue decreases compliance, making inspiration more difficult

Question 3

According to Boyle's Law, what happens to intra-alveolar pressure ($$P_{alv}) $$when the volume of the thoracic cavity increases during inspiration?

Accepted Answer

$$P_{alv}$$ decreases, causing air to flow into the lungs

Question 4

Which of the following equations correctly represents the relationship between air flow, pressure gradient, and airway resistance in the lungs?

Accepted Answer

$$Flow = \frac{P_{atm} - P_{alv}}{R}$$

Question 5

A person is exposed to high levels of histamine due to an allergic reaction. What is the expected effect on their airway resistance and why?

Accepted Answer

Airway resistance increases due to bronchoconstriction and increased mucus secretion

Question 6

Calculate the alveolar ventilation for a person with a tidal volume ($$V_T) of 600 mL$$, a respiratory rate (RR) of 10 breaths/min, and an anatomical dead space (DSV) of 150 mL. Use the formula: $$Alveolar\ Ventilation = (V_T 	imes RR) - (DSV 	imes RR).$$

Accepted Answer

$$Alveolar\ Ventilation = (600 	imes 10) - (150 	imes 10) = 6000 - 1500 = 4500\ mL/min$$

Question 7

Which of the following is a characteristic of obstructive pulmonary diseases such as asthma or COPD?

Accepted Answer

Increased residual volume and decreased vital capacity

Question 8

What is the primary role of surfactant in the alveoli?

Accepted Answer

Decreasing surface tension to increase lung compliance

Question 9

During quiet expiration, which muscles are primarily involved?

Accepted Answer

No muscles actively contract; expiration is passive due to lung recoil

Question 10

A patient at sea level has an intra-alveolar pressure ($$P_{alv}) of -2 mm Hg $$during inspiration. What is the direction of airflow and why?

Accepted Answer

Air flows into the lungs because $$P_{alv} is $$less than atmospheric pressure

Question 11

Which of the following best explains why the intrapleural pressure is always negative under normal conditions?

Accepted Answer

It prevents the lungs from collapsing by keeping the lung wall and chest wall together

Question 12

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

Accepted Answer

Gas exchange between air and blood

Question 13

A person with a tidal volume ($$V_T) of 500 mL $$and a respiratory rate (RR) of 12 breaths/min has a minute ventilation of:

Accepted Answer

$$500\ mL 	imes 12\ breaths/min = 6000\ mL/min$$

Question 14

Which of the following changes would most likely increase airway resistance?

Accepted Answer

Bronchoconstriction due to parasympathetic stimulation

Question 15

Which of the following best describes the effect of increased surface tension in the alveoli?

Accepted Answer

Decreases lung compliance, making inspiration more difficult

Question 16

Which of the following is a distinguishing feature of restrictive pulmonary diseases?

Accepted Answer

Decreased lung compliance and reduced total lung capacity

Question 17

Which cell type is responsible for secreting surfactant in the alveoli?

Accepted Answer

Type II alveolar cells

Question 18

Which of the following mechanisms helps enhance venous return to the heart during inspiration?

Accepted Answer

Decreased thoracic pressure draws blood toward the heart

Question 19

Which of the following best describes the role of the mucus escalator in the conducting zone?

Accepted Answer

It moves trapped particles and pathogens toward the pharynx for removal

Question 20

A person at high altitude experiences a decrease in atmospheric pressure ($$P_{atm}). $$How does this affect the pressure gradient for pulmonary ventilation?

Accepted Answer

The pressure gradient decreases, making inspiration less effective

Chapter 17: Mechanics of Breathing and Pulmonary Ventilation: Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards