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 volumewhich widens the caliber of extralveolar vessels

Question

Quizplus · Accepted Answer

All three factors contribute to the reduction in pulmonary vascular resistance following the first breath. Increased alveolar oxygen pressure causes vasodilation of the pulmonary vessels, removal of lung fluid decreases external pressure on the vessels, and an increase in lung volume during inspiration widens the extralveolar vessels, all of which decrease resistance.

What of the Following Factors Cause a Reduction in the Pulmonary