Microcirculatory network structures and models.

Terminal vascular beds exhibit a high degree of heterogeneity. Pertinent parameters are nonlinearly related, and their distributions are not independent. The classical "typical vessel" approach using averaged values for different vessel classes may not lead to a correct understanding of physiology and pathophysiology of terminal vascular beds. Such problems can be avoided by studying microcirculatory functions at the network level using a combination of experiments and theoretical models. In this approach, distributions and relationships of pertinent parameters are measured in vivo, leading to the development of comprehensive databases. Such databases can be analyzed and complemented by suitable mathematical models, permitting estimation of parameters that are difficult to measure, and critical assessment of quantitative theories and hypotheses for microvascular function. This collaborative process between experimentally and theoretically oriented investigators may be facilitated in the future by the development of web-based repositories of experimental data and theoretical models.