[Changes of blood flow structure in precapillary microvessels during significant slow-down of flow]. / Izmeneniia v strukture potoka krovi v mikrososudakh prekapilliarnogo tipa pri ego zhachitel'nom zamedlenii.

ABSTRACT

The experiments were carried out with a special "biological model" in which the rabbits' red blood cell suspension possessing low hematocrit circulated in frogs' mesenterial microvessels. Red blood cell behaviour was investigated in microvessels of 19-45 microns in diameter under conditions of arbitrarily changed flow velocity in mesenterial microvessels. Automatic frame-to-frame analysis of cinematographic films with the texture analysis system (Ernst Leitz, FRG) showed that the velocity fluctuations of individual red blood cells and their radial displacements increased significantly, while their velocity profile became blunt, during slowing-down of flow from 0.7 to 0.2 mm/s. Thus the normal blood flow structure in microvessels becomes disordered under ischemic conditions entailing disturbance of blood rheological properties and creating additionally increased resistance in the vessels.