Synchronization of Cellular Contractions in the Arteriolar Wall

Abstract

With few exceptions all tissues in the mammalian body are invested by a highly branched microcirculatory network. The microcirculation serves to bring the blood into close contact with every part of the tissue. In this way the exchange between blood and tissue of oxygen, nutrients, metabolic bi-products, etc. can be bridged efficiently by diffusion. Like most other hollow structures in the body, the wall of arterioles and small muscular arteries (resistance vessels) are invested with a specific kind of contractile cell known as the smooth muscle cell(SMC). The SMC is long and spindle shaped. Under the microscope its interior does not appear as highly organized as, for instance, the cells of skeletal muscle tissue. In the latter kind of cells the structure of the contractile machinery can be directly observed, but this is not the case for the SMC. In addition, contraction or relaxation of the SMC is involuntary, i.e. we cannot control it by will. For a number of reasons, however, the contractile characteristics of the SMC make it well suited to participate in the regulation of our internal milieu.