Butler J P, Banzett R B, Fredberg J J
Department of Environmental Science and Physiology, Harvard School of Public Health, Boston, MA 02115.
Respir Physiol. 1988 May;72(2):241-55. doi: 10.1016/0034-5687(88)90010-2.
The presence of unidirectional flow in the avian lung is thought to be effected by aerodynamic 'valves'. First we review the history of this hypothesis and summarize existing evidence. Second, we present a semiquantitative treatment of the various fluid dynamic factors that may be involved in directing fluid flow. The resulting calculations show in some detail how the inspiratory valve may work, and upon what mechanisms it may depend. Our calculations suggest that gas convective inertial forces are sufficient to effect inspiratory valving. Finally, we give some heuristic arguments regarding the mechanisms of expiratory valving.
鸟类肺部单向气流的存在被认为是由空气动力学“瓣膜”所实现的。首先，我们回顾这一假说的历史并总结现有证据。其次，我们对可能参与引导流体流动的各种流体动力学因素进行半定量分析。所得计算结果详细展示了吸气瓣膜可能的工作方式及其可能依赖的机制。我们的计算表明，气体对流惯性力足以实现吸气瓣膜作用。最后，我们就呼气瓣膜的机制给出一些启发性观点。
