[In vivo study of erythrocyte orientation in microvessels and the effect of different factors on it]

The orientation of erythrocytes in frogs' mesenteric microvessels (25--35 micrometer) depends on the following factors: a) linear velocity of erythrocytes, b) their concentration in the blood strain and c) character of the stream--its uniformity as well as presence of accelerations. At the velocity of red cells below 0.3 mm/sec the orientation of erythrocytes is essentially perpendicular to the vascular walls and readily affected by the stream character. The erythrocyte orientation becomes parallel to the stream direction and is not influenced by its character when the red cell velocity is over 0.3--0.4 mm/sec.