Mammalian lung, alveolar surfaces

For the analysis of extracellular glycolipids of respiratory tract, we have chosen the acellular material lining the alveoli of mammalian lungs. This unique lipid-protein mixture, responsible for the reduction of alveolar surface forces during respiration,... 

Ultimately, the air with its remaining contaminants reaches the pulmonary region, which is the most distal and includes the respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli. The main purpose of the alveolar architecture of the mammalian lung is to expose blood to gas over a large surface area within a comparatively small volume. 

The surface tension of the tracheal wall in the normal rat, guinea pig, sheep, and horse is approximately 32-33 mN/m, substantially more than the plateau surface tension (23-25 mN/m) of alveolar surfactant extracts from mammalian lungs. These data are consistent with recent studies in the pig, using relatively pure extracts of tracheal fluid, that have shown that the surface tension properties of tracheal fluid are considerably less than those of BAL fluid (44). 

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