Capillary networks are the principal sites at which oxygen is transported from red blood cells (RBC) to muscle and other tissues. In skeletal muscle, capillaries have often been modeled as collections of parallel vessels, all containing the same concentration of oxygen. However, in reality there exist complexities in network geometry which affect both diffusive and convective transport and lead to heterogeneity in the supply of oxygen. In addition, the characteristics of blood flow and oxygen transport heterogeneities are different at rest and during exercise. Currently, it is not known what type of oxygen supply heterogeneities are produced by realistic network architecture and RBC distribution. In this work, the large amount of experimental data available on capillary network geometry and hemodynamics is used to study realistic capillary networks in skeletal muscle, in order to determine the physiological significance of complexities in network architecture. A geometric model is constructed and blood flow and oxygen transport are simulated, using adaptations of existing models, for conditions of rest and exercise. The simulation data is then studied using both traditional statistical methods and recently developed mathematical techniques for analyzing spatiotemporal complexity.
