Mass transport in mammalian lungs: comparative physiology.

Comparative physiology of mass transport of gases in mammalian lungs is surveyed in terms of the use of experimental mammals in inhalation toxicology. Principles of similarity, scaling, and the relationship of metabolism to body size are touched on, with reference to the wide variability among mammals of similar size. Mechanisms that influence the magnitude and distribution of pulmonary ventilation are reviewed, including mechanical differences associated with variation in body size. More systematic and complete descriptions and understanding are needed. Recent advances in the understanding of gas mixing and transport in airways and in the pulmonary acinus have applications in comparative physiology and inhalation toxicology that are worth exploring.