Baba K, Kawamura T, Shibata M, Sohirad M, Kamiya A
Institute of Medical Electronics, Faculty of Medicine, University of Tokyo, Japan.
Microvasc Res. 1995 Mar;49(2):163-79. doi: 10.1006/mvre.1995.1013.
The aim of this computer simulation study is to evaluate the efficiency of capillary networks in the skeletal muscle for oxygen (O2) delivery to tissue for all mammals. This was performed by: (1) employing Krogh's cylinder model for the capillary-tissue system and the minimum volume model for the vascular system, (2) allometrically assessing the muscle blood flow and O2 consumption rate (the main input data) in the resting and exercising states as power functions of body weight from the data reported for several mammals, and (3) calculating the cost-performance of the system from the ratio (maximum O2 uptake of tissue)/(minimum energy expenditure of blood flow supply), as a function of number of capillaries. The results obtained for body weights ranging from 100 g to 1000 kg revealed that for each body weight and metabolic state, the efficiency curve attains a peak at a specific optimum capillary number, and that the calculated values of total muscle mass, capillary density, and capillary flow-rate by using the optimum capillary number and tissue radius during exercise agree remarkably well with those actually measured in various animals. These findings suggest the validity of a working hypothesis that in all mammals, the capillary arrangement in the skeletal muscle is optimized for O2 delivery to tissue during exercise.
这项计算机模拟研究的目的是评估所有哺乳动物骨骼肌中毛细血管网络向组织输送氧气（O2）的效率。研究通过以下方式进行：（1）采用克罗格圆柱体模型来描述毛细血管 - 组织系统，采用最小体积模型来描述血管系统；（2）根据几种哺乳动物报告的数据，将静息和运动状态下的肌肉血流量和氧气消耗率（主要输入数据）按体重的幂函数进行异速生长评估；（3）根据（组织的最大氧气摄取量）/（血流供应的最小能量消耗）的比率计算系统的性价比，并将其作为毛细血管数量的函数。对于体重在100克至1000千克范围内的研究结果表明，对于每种体重和代谢状态，效率曲线在特定的最佳毛细血管数量处达到峰值，并且在运动期间使用最佳毛细血管数量和组织半径计算得到的总肌肉质量、毛细血管密度和毛细血管流速值与在各种动物中实际测量的值非常吻合。这些发现表明了一个工作假设的有效性，即在所有哺乳动物中，骨骼肌中的毛细血管排列在运动期间针对向组织输送氧气进行了优化。
