Q: Given atmospheric pressure ($$P_{atm}) is 760 $$mmHg and water vapor pressure ($$P_{H_2O}) is 47 $$mmHg, what is the partial pressure of oxygen ($$P_{O_2$}) in $$dry air if oxygen makes up 21% of the mixture? Use Dalton’s Law.

$$P_{O_2$} = 0.21 \times (760 - 47) = 149$$ mmHg

Question 1

Which of the following is NOT a major function of the respiratory system?

Accepted Answer

Regulation of blood glucose levels

Question 2

During inspiration, which sequence correctly lists the order of respiratory structures that air passes through, starting from the external environment?

Accepted Answer

Nasal cavity → pharynx → larynx → trachea → bronchi → bronchioles → alveoli

Question 3

Which of the following best describes the structural difference between the trachea and the respiratory bronchioles?

Accepted Answer

The trachea contains C-shaped cartilage rings, while respiratory bronchioles lack cartilage and have more smooth muscle.

Question 4

Which cell type is primarily responsible for producing surfactant in the alveoli, and what is the main function of surfactant?

Accepted Answer

Type II alveolar cells; reducing surface tension to prevent alveolar collapse

Question 5

Given atmospheric pressure ($$P_{atm}) is 760 $$mmHg and water vapor pressure ($$P_{H_2O}) is 47 $$mmHg, what is the partial pressure of oxygen ($$P_{O_2$}) in $$dry air if oxygen makes up 21% of the mixture? Use Dalton’s Law.

Accepted Answer

$$P_{O_2$} = 0.21 	imes (760 - 47) = 149$$ mmHg

Question 6

According to Boyle’s Law, what happens to the pressure of a gas if the volume of its container is doubled, assuming temperature and amount of gas remain constant?

Accepted Answer

The pressure is halved.

Question 7

Which of the following lung volumes cannot be measured directly by spirometry?

Accepted Answer

Residual volume (RV)

Question 8

During a normal quiet breathing cycle, when is alveolar pressure ($$P_{alv}) $$equal to atmospheric pressure ($$P_{atm}$$)?

Accepted Answer

At the end of inspiration and at the end of expiration

Question 9

Which of the following best explains why intrapleural pressure is subatmospheric at the end of a quiet expiration?

Accepted Answer

The elastic recoil of the lungs pulling inward and the chest wall pulling outward create a slight vacuum in the pleural cavity.

Question 10

According to the Law of Laplace, what effect does surfactant have on alveoli of different sizes?

Accepted Answer

Surfactant reduces surface tension more in smaller alveoli, preventing their collapse.

Question 11

Which of the following factors would most likely cause bronchoconstriction?

Accepted Answer

Increased parasympathetic stimulation

Question 12

A patient is experiencing an asthma attack, which involves excessive bronchoconstriction. What is the most immediate effect on airway resistance and pulmonary ventilation?

Accepted Answer

Airway resistance increases, and pulmonary ventilation decreases.

Question 13

Which of the following best describes the difference between total pulmonary (minute) ventilation and alveolar ventilation?

Accepted Answer

Total pulmonary ventilation includes all air moved in and out of the lungs, while alveolar ventilation only includes air reaching the alveoli for gas exchange.

Question 14

If a person hyperventilates for two minutes, what is the expected change in alveolar $$CO_2$$ concentration?

Accepted Answer

Alveolar $$CO_2$$ concentration decreases.

Question 15

Which local control mechanism helps match ventilation and perfusion in the lungs?

Accepted Answer

Low alveolar $$O_2$$ causes constriction of pulmonary arterioles, redirecting blood to better-ventilated alveoli.

Question 16

A patient is rebreathing air from a paper bag for two minutes. What is the most likely effect on their alveolar $$CO_2$$ and $$O_2$$ levels?

Accepted Answer

Alveolar $$CO_2$$ increases and alveolar $$O_2$$ decreases.

Question 17

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

Accepted Answer

$$VC = IRV + TV + ERV$$

Question 18

Which of the following best describes the function of ciliated epithelial cells in the respiratory tract?

Accepted Answer

They move mucus and trapped particles upward toward the pharynx as part of the mucociliary escalator.

Question 19

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

Accepted Answer

$$Alveolar\ Ventilation = (TV - Dead\ Space) 	imes Respiratory\ Rate = (500 - 150) 	imes 12 = 4,200\ mL/min$$

Question 20

Which of the following would most likely increase airway resistance?

Accepted Answer

Constriction of bronchiolar smooth muscle

Chapter 18: Pulmonary Mechanics – Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards