Question 1

Which of the following best describes the primary function of the respiratory system?

Accepted Answer

To obtain O$$_2$$ for the body's cells and eliminate CO$$_2$$ produced by cellular metabolism

Question 2

During cellular respiration, what is the respiratory quotient (RQ) if a person produces 200 ml/min of CO$$_2$$ and consumes 250 ml/min of O$$_2$$?

Accepted Answer

$$RQ = \frac{CO_2$\ produced}{O_2$\ consumed} = \frac{200}{250} = 0.8$$

Question 3

Which law explains why increasing the volume of the thoracic cavity during inspiration decreases the pressure inside the alveoli?

Accepted Answer

Boyle's Law: $$P_1V_1 = P_2V_2$$

Question 4

What is the effect of alveolar surfactant on the alveoli?

Accepted Answer

It decreases surface tension, promoting alveolar stability and reducing the work of breathing

Question 5

During expiration, which of the following pressure relationships is correct for air to flow out of the lungs?

Accepted Answer

Intra-alveolar pressure $$\u003e$$ atmospheric pressure

Question 6

Which structure is the primary site of gas exchange in the lungs?

Accepted Answer

Alveoli

Question 7

A patient with decreased alveolar surfactant is likely to experience which of the following?

Accepted Answer

Decreased lung compliance and increased work of breathing

Question 8

Which of the following best describes the mechanics of breathing during inspiration?

Accepted Answer

Thoracic cavity volume increases, intra-alveolar pressure decreases

Question 9

Which pressure is always lower than atmospheric pressure during normal, quiet breathing?

Accepted Answer

Intrapleural pressure

Question 10

Which of the following is a non-respiratory function of the respiratory system?

Accepted Answer

Maintaining acid-base balance

Question 11

If the volume of the thoracic cavity is halved during forced expiration, what happens to the pressure inside the alveoli according to Boyle's Law?

Accepted Answer

Pressure is doubled

Question 12

Which muscle is primarily responsible for increasing thoracic cavity volume during quiet inspiration?

Accepted Answer

Diaphragm

Question 13

What is the main reason gas exchange occurs rapidly across the alveolar-capillary membrane?

Accepted Answer

The membrane is thin and has a large surface area

Question 14

Which of the following best explains the direction of airflow during breathing?

Accepted Answer

Air moves from higher pressure to lower pressure down its pressure gradient

Question 15

A patient with pleurisy is likely to experience which of the following symptoms?

Accepted Answer

Pain due to inflammation of the pleural membranes

Question 16

Which of the following statements about the pleural cavity is correct?

Accepted Answer

It contains intrapleural fluid that lubricates the pleural surfaces

Question 17

During the respiratory cycle, when is there no airflow into or out of the lungs?

Accepted Answer

When intra-alveolar pressure equals atmospheric pressure

Question 18

Which of the following best describes the role of pulmonary capillaries in external respiration?

Accepted Answer

They facilitate the diffusion of O$$_2$$ and CO$$_2$$ between alveoli and blood

Question 19

A person is experiencing difficulty breathing due to increased surface tension in the alveoli. Which of the following treatments would most directly address this issue?

Accepted Answer

Administration of artificial surfactant

Respiratory Physiology: Alveoli, Gas Laws, & Respiratory Cycle

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