Question 1

During quiet breathing (eupnea), which of the following best describes the role of muscular force in inspiration and expiration?

Accepted Answer

Muscular force is used for inspiration but not expiration.

Question 2

Which pressure is most important in keeping the lungs from collapsing?

Accepted Answer

Intrapleural pressure

Question 3

A patient with COPD has degraded elastin protein, resulting in less recoil of the lungs. How would this affect intrapleural pressure and why?

Accepted Answer

Intrapleural pressure would be less negative because less recoil would lead to less inward pull on the pleura.

Question 4

Which of the following best describes the process of ventilation?

Accepted Answer

Muscles cause the volume of the thoracic cavity to change.

Question 5

Which equation correctly represents the relationship between atmospheric pressure ($$P_{atm}$$), intrapulmonary pressure ($$P_{pul}$$), and airflow direction during inspiration?

Accepted Answer

$$P_{atm} \u003e P_{pul}$$; air flows into the lungs

Question 6

The exchange of gases between blood and the air in the lungs is known as:

Accepted Answer

External Respiration

Question 7

Pleural effusion is a condition where fluid accumulates in the pleural cavity. Which pressure or pressures would you expect to be most directly impacted by this fluid accumulation?

Accepted Answer

Intrapleural pressure

Question 8

If air enters the pleural cavity (pneumothorax), what happens to the pressure relationships and why does the lung collapse?

Accepted Answer

Intrapleural pressure increases toward atmospheric pressure, eliminating the negative pressure that keeps the lung inflated.

Question 9

Which of the following factors contributes to resisting the tendency of the lungs to collapse?

Accepted Answer

Intrapleural pressure

Question 10

True or false: In healthy lungs, the intrapulmonary pressure is always lower than the intrapleural pressure.

Accepted Answer

False, the intrapulmonary pressure is only lower during some parts of ventilation.

Question 11

During forced expiration, which muscles are primarily involved?

Accepted Answer

Internal intercostals and abdominal muscles

Question 12

Which of the following best explains why the lungs do not collapse under normal conditions?

Accepted Answer

The negative intrapleural pressure counteracts the elastic recoil and surface tension.

Question 13

Which of the following is a passive property of the lungs that contributes to their tendency to collapse?

Accepted Answer

Elasticity/recoil

Question 14

Which of the following best describes the role of pulmonary surfactant?

Accepted Answer

It decreases surface tension, helping to keep alveoli open.

Question 15

Which formula best represents the relationship between pressure and volume in the lungs during ventilation (Boyle's Law)?

Accepted Answer

$$P 	imes V = k$$

Question 16

During external respiration, which of the following occurs?

Accepted Answer

Oxygen and carbon dioxide are exchanged between alveoli and blood.

Question 17

Which of the following would most likely occur if the intrapleural pressure equaled atmospheric pressure?

Accepted Answer

The lungs would collapse.

Question 18

Which structure in the thoracic cavity can change size significantly to allow for ventilation?

Accepted Answer

The lungs

Question 19

Which of the following best describes the function of hemoglobin in respiration?

Accepted Answer

It increases the amount of O$$_2$$ and CO$$_2$$ that can be carried in the blood.

Ventilation and Respiration: Mechanics and Pressure Relationships in the Lungs

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