- The alveolar pressure becomes greater (i.e., becomes positive) because alveolar gas is compressed by the elastic forces of the lung.

- Thus, alveolar pressure is now higher than atmospheric pressure, the pressure gradient is reversed, and air flows out of the lungs.

b. Intrapleural pressure returns to its resting value during a normal (passive) expiration.

- However, during a forced expiration, intrapleural pressure actually becomes positive. This positive intrapleural pressure compresses the airways and makes expiration more difficult.

- In chronic obstructive pulmonary disease (COPD), in which airway resistance is increased, patients learn to expire slowly with "pursed lips" to prevent the airway collapse that may occur with a forced expiration.

c. Lung volume returns to FRC.

Was this article helpful?

0 0
Delicious Diabetic Recipes

Delicious Diabetic Recipes

This brilliant guide will teach you how to cook all those delicious recipes for people who have diabetes.

Get My Free Ebook

Post a comment