[Ansiform growth of blood vessels as a fundamental principle of angiogenesis].

Succession in formation of blood bed of the greater omentum has been studied in human fetuses (42), in premature children with the body mass of 900-2,500 g (108) and in mature children up to 3 years of age (48). Vasculogenesis in the organ of 12-week-old fetuses and in older ones is demonstrated as an ansiform growth of the vessels. In the vascular loop the afferent geniculum contains differential signs of the arterial, and the different one--the venous part of the blood bed. The top of the loop contains a growth bud and is a zone of growth; it ensures proliferation of the vascular loops and their spreading in the growing tissue mass in the organ. This principle of growth provides a ramified system of arteries and veins, reiterating the course and branching of each other. Against the background of the ansiform growth of the vessels capillary formation begins, at first connective, and then true capillaries are formed. Basing on the data obtained a conception of vasculogenesis in ontogenesis is formulated. Its main stages are--period of ansiform growth of the vessels and period of capillary formation. In the latter should be distinguished appearance of connective capillaries and formation of truely capillary network.