The microcirculation: the connection to everything

In the cardiovascular system, the microcirculation constitutes the very smallest blood vessels; arterioles which allow for the delivery of oxygenated blood to an organ, capillaries which allow for optimal diffusion conditions for oxygen from the blood to the parenchymal cells and venules which transport deoxygenated blood back toward the heart. The importance of microcirculation is particularly evident in tissues in which oxygen consumption can be substantially altered, such as in skeletal muscle. Skeletal muscle microcirculation is unique in its ability to accommodate this requirement of rapid, precise, and very large changes in muscle oxygen uptake. The structural make-up of skeletal muscle with long muscle fibers that change substantially in length during contraction, also calls for a highly specialized microvascular architecture. This chapter covers how structure, hemodynamics, and regulatory properties of the microcirculation, via an intricate interaction, allow for precise delivery of oxygen to the tissue with emphasis on skeletal muscle.