Standard Article

Pulmonary Circulation in Extreme Environments

  1. G. Kim Prisk

Published Online: 1 JAN 2011

DOI: 10.1002/cphy.c090006

Comprehensive Physiology

Comprehensive Physiology

How to Cite

Prisk, G. K. 2011. Pulmonary Circulation in Extreme Environments. Comprehensive Physiology. 1:319–338.

Author Information

  1. Departments of Medicine and Radiology, University of California, San Diego

Publication History

  1. Published Online: 1 JAN 2011

Abstract

The pulmonary circulation is subject to direct challenge from both altered pressure and altered gravity. To efficiently exchange gas, the pulmonary capillaries must be extremely thin-walled and directly exposed to the alveolar space. Thus, alterations in ambient pressure are directly transmitted to the capillaries with the potential to alter pulmonary blood flow. To produce ventilation, the mammalian lung must expand and contract, and so it is a highly compliant structure. Thus, because the capillaries are contained in the alveolar walls, alterations in the apparent gravitational force deform the lung and directly affect pulmonary blood flow both through lung deformation and through changes in the hydrostatic pressure distribution in the lung. High gravitational forces are encountered in the aviation environment, while gravity is absent in spaceflight. Diving subjects the lung to large increases in ambient pressure, while large reductions in pressure occur, often associated with alterations in oxygen level and airway pressure, in aviation. This article reviews the effects of alterations in both gravity and ambient pressure on the pulmonary circulation. © 2011 American Physiological Society. Compr Physiol 1:319-338, 2011.