What of the following factors cause a reduction in the pulmonary vascular resistance following the first breath?
I. Increased alveolar pressure of oxygen
II. Removal of lung fluid which reduces pressure on pulmonary vessels
III. Increase in lung volume, which widens the caliber of extralveolar vessels

Question

Quizplus · Accepted Answer

The reduction in pulmonary vascular resistance following the first breath is due to increased alveolar oxygen pressure, which causes vasodilation; removal of lung fluid, which decreases external pressure on the pulmonary vessels; and an increase in lung volume, which widens the caliber of extralveolar vessels, all contributing to decreased resistance.

What of the Following Factors Cause a Reduction in the Pulmonary