[Structuro-functional features of different links in the microhemocirculatory bed of the myocardium]

Morphofunctional peculiarities of various elements of the microhemocirculatory bed (MHCB) of the myocardium performing correction of the nutritive blood stream, structures and mechanisms of the microvessel permeability have been studied. The investigation has been performed on 20 mature rabbits and 5 mongrel dogs, transmissive electron microscopy and certain cytochemical techniques applied for revealing ATP-ase, lactate-, malate-, succinate-dehydrogenases, cytochrome-C-reductase and glycosamine glycans. Structural differences in microvessels of various range are described. Together with smooth muscle cells in arterioles and precapillary sphincters, specialized endotheliocytes and valve-like formations, situating in the orifices of blood capillaries, participate in regulation of hemoperfusion of the MHCB functional units. The data have been obtained characterising cytolemma of the endotheliocytes as a complex system, where plasmolemma, being the bearer of ATP-ase and a complex of oxidoreductase, regulates physical-chemical properties of the paraplasmolemmal layer and ensures the control of all the forms of the transcapillary transport. Micropinocytic vesicles are proved to differentiate into two functionally asynonymous populations: one of them performs the energy-dependent transport, while the other reserves the plasmolemma.