Popel A S, Liu A, Dawant B, Koller A, Johnson P C
Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205.
Am J Physiol. 1988 Jun;254(6 Pt 2):H1149-56. doi: 10.1152/ajpheart.1988.254.6.H1149.
Morphometric information on the terminal arteriolar networks (n = 10) in cat sartorius muscle [Koller et al., Am. J. Physiol. 253 (Heart Circ. Physiol. 22): H154-H164, 1987] is utilized in the calculations of distribution of vascular hindrance throughout the networks. These networks have tree-type geometry, i.e., they do not contain closed loops. The results are discussed in terms of simulated flow distribution. The flow calculations are based on the exact geometry of the arteriolar networks (the control and dilated diameter and the length of each vascular segment) and on assumed values of postarteriolar resistances. Three cases of postarteriolar resistances are considered: zero, constant, and randomly distributed. With zero postarteriolar resistances, the distribution of flow in the terminal arteriolar segments would be highly heterogenous. The simulated flow in each terminal segment is determined primarily by the number of bifurcations on the pathway leading to the terminal segment, with a slight compensation for the length of the pathways. The coefficient of variation of flow in the control state, CV(Qc), would be close to the value in the dilated state, CV(Qd). When each of the terminal segments is connected to a constant postarteriolar resistance, the CV's in both states decrease. The coefficient of variation in the dilated state becomes significantly smaller than in the control state. When postarteriolar resistances are randomly distributed, both CV's increase, and their values become closer to each other. These results suggest that postarteriolar resistances may play a very important role in distribution of flow in the microvascular network. This study formulates a framework for the quantification of the effect of arteriolar dilation on flow redistribution in the network.
利用猫缝匠肌终末小动脉网络（n = 10）的形态测量信息[科勒等人，《美国生理学杂志》253卷（心脏循环生理学22）：H154 - H164，1987年]来计算整个网络中血管阻力的分布。这些网络具有树状几何结构，即不包含闭环。根据模拟的血流分布对结果进行了讨论。血流计算基于小动脉网络的精确几何结构（每个血管段的对照和扩张直径以及长度）以及小动脉后阻力的假设值。考虑了三种小动脉后阻力情况：零、恒定和随机分布。当小动脉后阻力为零时，终末小动脉段中的血流分布将高度不均匀。每个终末段中的模拟血流主要由通向该终末段的路径上的分支数量决定，并对路径长度有轻微补偿。对照状态下血流的变异系数CV(Qc)将接近扩张状态下的值CV(Qd)。当每个终末段连接到恒定的小动脉后阻力时，两种状态下的CV均降低。扩张状态下的变异系数变得明显小于对照状态。当小动脉后阻力随机分布时，两个CV均增加，且它们的值彼此更接近。这些结果表明，小动脉后阻力可能在微血管网络的血流分布中起非常重要的作用。本研究为量化小动脉扩张对网络中血流再分布的影响制定了一个框架。
