The Static Versus the Dynamic State of the Microvasculature

Abstract

The raison d’être of the microcirculatory system is the adequate supply of oxygen-carrying red blood cells to the most minute interstices of an organ. The rate at which this process takes place is determined in part by the static mechanical properties of the microvasculature, including spatial architectural relationships, and fluid mechanical phenomena. These properties do not have precise and unique magnitudes but are variable and exhibit a statistical distribution that implies a local variability of blood flow; consequently, in the static microvasculature, some given microscopic domains can be more adequately perfused than others; therefore, as a consequence of this inhomogeneity, localized microscopic regions where cellular survival is marginal can be present in the tissues. A fundamental question is whether these static mechanical characteristics have a real physiological significance in terms of maintaining tissue homeostasis in normal conditions, since the range of local adjustment of the blood supply that these mechanisms allow for is, at best, limited.