Microcirculatory Flow Patterns

Old descriptive studies of microcirculation must be reexamined. Many studies (Holland and Meyer, 1919; Jaensch, 1929) concerned with the normal, as contrasted with abnormal, development of the nailfold capillaries in infants showed that the pattern of hairpinlike loops developed at a basic rate, the loops arising from a subpapillary arteriolar plexus and reentering a venular subpapillary plexus. The mature capillary pattern is usually completed between 6 and 12 months after birth. Development of surface capillary loops in man has been fairly well documented for half a century. Heat regulation is the main function of surface vessels; its demands start early (Redisch et al., 1957). Whether other beds follow similar patterns of response to changing metabolic needs during growth remains conjectural. The emergence of known architectural peculiarities in some adult beds makes such assumption plausible; however, documentation is lacking.