[Regularities in the formation of the hemomicrocirculation system in embryogenesis and its morphologic characterization in prematurity].

The development of the intraorgan vascular bed in human embryogenesis is brought about by the growth of vascular loops followed by formation of all types of vessels including hemomicrocirculation. Three stages in the formation of hemomicrocirculatory bed can be distinguished: stage I is the integration of vascular loops by means of main and connecting capillaries; stage II-unification of the connecting and main capillaries with true capillaries; stage III consists of formation of arterio-venular, veno-venular and arteriolo-arteriolar anastomoses. Prematurely born children have deficiency of true capillaries in the hemomicrocirculation system, this manifesting by a capillary circulation deficiency and that of transcapillary tissue metabolism. This deficiency is observed in all prematurely born children but its maximum expression is found in the prematurity of degree IV and III.