[Ultrastructural regularities of new growth of secondary micro blood vessels in the prenatal period of human morphogenesis].
By means of transmissive electron microscopy structural aspects of new formation of secondary blood microvessels in functionally different organs have been studied during fetal period of the human development. Growth buds appear on the basal surface of the endothelial lining of the blood microvessels predominantly in those areas of the vascular wall, where pericytes and adventitial cells are absent. The first stage in formation of the growth bud is separating of small compartments in the lumen of the maternal vessel. Then, connected by means of specialized contacts, endothelial cells of such a compartment move one by one towards periphery of the vessel and form the growth bud, protruding outside. In the area of the growth bud local destruction of the basal membrane is observed. Newly formed microvessels, anastomising, form vascular loops. Further processes in differentiation of separate segments of the newly formed capillary network into links of the hemomicrocirculatory bed are analogous to those, observed in the course of differentiation of the primary protocapillary network into the secondary intraorganic blood bed.
Bobrik
I I
II
Cherkasov
V G
VG
Shevchenko
E A
EA
D005333:Fetus / Q000033:anatomy & histology*; D006801:Humans; D008833:Microcirculation / Q000196:embryology* / Q000648:ultrastructure; D009024:Morphogenesis; D009389:Neovascularization, Pathologic
Ul'trastrukturnye zakonomernosti novoobrazovaniia vtorichnykh krovenosnykh mikrososudov v prenatal'nom periode morfogeneza cheloveka.