Ebert R V
Ann Intern Med. 1978 Jan;88(1):98-103. doi: 10.7326/0003-4819-88-1-98.
Recent findings have emphasized the importance of the bronchiole to the function of the lung. The surface of the bronchiole differs from that of the alveolus. Rather than being covered by a thin coat of phospholipid, the surface is covered with cilia that are surrounded by a low-viscosity fluid. This permits the removal of foreign particles. Surface forces are important to the function of the bronchiole. The diameter of the bronchiole is a function of the volume of the lung. When the lung is partially collapsed, the bronchiole acts as a capillary tube and is readily obstructed by fluid. In chronic bronchitis, obstruction is related to narrowing by fibrosis and inflammation, alteration in the secretion, and loss of traction on the walls. Obstruction of the bronchiole by fluid in edema of the lung contributes to hypoxemia. Positive end expiratory pressure may prevent obstruction by increasing the bronchiolar diameter.
最近的研究结果强调了细支气管对肺功能的重要性。细支气管的表面与肺泡的表面不同。其表面不是覆盖着一层薄薄的磷脂，而是覆盖着被低粘度液体包围的纤毛。这使得外来颗粒得以清除。表面力对细支气管的功能很重要。细支气管的直径是肺容积的函数。当肺部分萎陷时，细支气管起毛细管的作用，容易被液体阻塞。在慢性支气管炎中，阻塞与纤维化和炎症导致的狭窄、分泌物改变以及壁上牵引力丧失有关。肺水肿时液体对细支气管的阻塞会导致低氧血症。呼气末正压可通过增加细支气管直径来防止阻塞。
