Pulmonary surfactant: Surface properties and function of alveolar and airway surfactant
| Autor: | Martin M. Lee, Samuel Schürch, Peter Gehr |
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| Rok vydání: | 1992 |
| Předmět: | |
| Zdroj: | Pure and Applied Chemistry. 64:1745-1750 |
| ISSN: | 1365-3075 0033-4545 |
| DOI: | 10.1351/pac199264111745 |
| Popis: | The pulmonary surfactant film at the alveolar air-liquid interface reduces the surface tension to a value below 1 mN/m on lung deflation. In addition to a low and stable surface tension, interdependence provided by the fibrous continuum enables the lung to maintain a large alveolar surface area, necessary for an efficient gas exchange. Surface tension-area relations from lung surfactant extracts are obtained with a new apparatus that contains a captive bubble of controllable size. Upon 3-4 compressionexpansion cycles, surfactant films exhibit the low surface tensions, collapse rates and compressibilities characteristic of alveolar surfaces. Not only the alveoli but also the bronchi are covered by a surfactant film. Inhaled particles, when deposited in the airways or alveoli, are displaced by surface forces towards the epithelium where they are retained. Experiments in the Langmuir-Wilhelmy balance showed that pulmonary surfactant promotes the displacement of spherical latex particles from air to the aqueous phase. The extent of particle immersion depends on the surface tension of the surface active film. The lower the surface tension, the greater is the immersion of the particles into the aqueous subphase. Electron microscopy demonstrates that particles in peripheral airways and alveoli are found below the surfactant film and submerged in the subphase. This may promote clearance by macrophages. |
| Databáze: | OpenAIRE |
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