Where Breath Meets Blood—Lung Perfusion

James R. Munis

in Just Enough Physiology

Published on behalf of © Mayo Foundation for Medical Education and Research

Published in print December 2011 | ISBN: 9780199797790
Published online June 2012 | e-ISBN: 9780199929665 | DOI:

Series: Mayo Clinic Scientific Press

Where Breath Meets Blood—Lung Perfusion

More Like This

Show all results sharing this subject:

  • Professional Development in Medicine


Show Summary Details


The pulmonary circulation is a low-resistance, low-pressure, high-flow system because its primary function is to oxygenate blood. For that reason, pulmonary circulation is different from systemic circulation. Because resistance is lower in pulmonary circulation, pressures across the pulmonary vascular bed also are substantially lower. An efficient system includes inherently low resistance. This allows the entire cardiac output to flow through without high-pressure areas, thereby diminishing the danger of rupturing thin gas-exchange surfaces. One other consequence of low resistance is that the pulmonary circulation is unusually susceptible to the effects of gravity. No substantial part of the cerebral circulation collapses in the head-up position because it is held open by the rigid cranium and the architecture of the venous sinuses. Pulmonary circulation is different. There is less ‘stenting open’ of pulmonary capillaries, and they are therefore more likely to partially or fully collapse when transmural pressure becomes negative.

Chapter.  1617 words.  Illustrated.

Subjects: Professional Development in Medicine

Full text: subscription required

How to subscribe Recommend to my Librarian

Buy this work at Oxford University Press »

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.