Oxygen Concentration and Partial Pressure in the Alveoli

Oxygen is continually being absorbed from the alveoli into the blood of the lungs, and new oxygen is continually being breathed into the alveoli from the atmosphere. The more rapidly oxygen is absorbed, the lower its concentration in the alveoli becomes; conversely, the more rapidly new oxygen is breathed into the alveoli from the atmosphere, the higher its concentration becomes. Therefore, oxygen concentration in the alveoli, and its partial pressure as well, is controlled by

(1) the rate of absorption of oxygen into the blood and

(2) the rate of entry of new oxygen into the lungs by the ventilatory process.

Expiration of a gas from an alveolus with successive breaths.

Rate of removal of excess gas from alveoli

Expiration of a gas from an alveolus with successive breaths.

Rate of removal of excess gas from alveoli

Figure 39-4

Effect of alveolar ventilation on the alveolar Po2 at two rates of oxygen absorption from the alveoli— 250 ml/min and 1000 ml/min. Point A is the normal operating point.

Was this article helpful?

0 0
Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

Get My Free Ebook


Post a comment