An optimal bronchial tree may be dangerous
An optimal bronchial tree may be dangerous
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DOI：
10.1038/nature02287
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发表时间：
2004-02-12
期刊：
影响因子：
64.8
通讯作者：
Sapoval, B
中科院分区：
文献类型：
--
作者：
Mauroy, B;Filoche, M;Sapoval, B
分支结构如血管或气道的几何形状和尺寸是决定生理过程效率的重要因素。已经表明，分形树可以填充空间（1），并可以确保最小的耗散（2-4）。大多数哺乳动物肺的支气管树是具有近似分形结构的有效分布系统的一个很好的例子（5，6）。在这里，我们提出了一个研究的兼容性之间的物理优化和生理鲁棒性的设计，人体支气管树。我们表明，这种物理优化是至关重要的，在这个意义上说，小的变化的几何形状可以引起非常大的变化，净空气通量。因此，最大物理效率不能作为支气管树生理设计的充分标准。相反，支气管树的设计必须具有安全系数和调节气道口径的能力。奇怪的是，我们的研究结果表明，支气管功能障碍相关的哮喘是一个必要的后果，优化效率的树结构。
The geometry and dimensions of branched structures such as blood vessels or airways are important factors in determining the efficiency of physiological processes. It has been shown that fractal trees can be space filling(1) and can ensure minimal dissipation(2-4). The bronchial tree of most mammalian lungs is a good example of an efficient distribution system with an approximate fractal structure(5,6). Here we present a study of the compatibility between physical optimization and physiological robustness in the design of the human bronchial tree. We show that this physical optimization is critical in the sense that small variations in the geometry can induce very large variations in the net air flux. Maximum physical efficiency therefore cannot be a sufficient criterion for the physiological design of bronchial trees. Rather, the design of bronchial trees must be provided with a safety factor and the capacity for regulating airway calibre. Paradoxically, our results suggest that bronchial malfunction related to asthma is a necessary consequence of the optimized efficiency of the tree structure.