The structural picture of the arterial wall in preparations close to true life conditions and its physiologic and pathologic significance

Abstract

At first sight it seems impossible to obtain a picture of arterial structure fixed in the true conditions of life. The arterial wall particularly is exposed to severe forces of alteration at the moment of death. Even before autolysis and rigor mortis, it is submitted to a triple trauma: the sudden cessation of rhythmical pulsation, the emptying of the lumina and the blood coagulation. Nevertheless precisely, these factors give us a simple and relatively safetest for deciding whether a histological preparation corresponds to the true life conditions; we may assume this to be so when the lumen of small blood vessels is full ofuncoagulated blood. Studies on such preparations show that during life there are no particular annular and longitudinal muscle fibres in the arterial wall, it is rather theplasticity and activity of a unitary musculature which determines the appearance of variously oriented fibers in histological preparations. As for the elastic tissue, it appears as a continuous line, when in activity; curvatures or ruptures mean a limitation or suppression of the elastic function. Observations on the so-called regulating apparatus in arteries of man, completed by others on dogs under influence of adrenalin, lead one to consider the particular relationship of clear muscle cells and elastic elements as themorphological equivalent of vasoconstrictive action. These results call for a revision of some histological, histopathological and even physiological concepts, such as the accepted histological views on the existence of arterial closure apparatus. The aspects described as sphincters, “Polster”, “bourrelets”, valves are not permanent structures butsnapshots of moving parts of the arterial wall. The clear muscular cells named “epitheloid cells”, “Quellzellen”, Leiomyoblasts are muscle fibers quasi surprised by the fixation in theactive state.