[Analysis of the structural parameters of the blood flow pathways in the microcirculatory system]

The reconstruction of the mesenterium microcirculatory bed was performed intravitally in albino rats and cats after biomicrophotograms. The number, length and caliber of arterioles, pericapillary arteriolec, capillaries, postcapillary venules and venules of the mesenterium were measured. According to these data summary indices of the cross section, surface and volume of the vessels of various functional subdivisions of the microcirculatory bed were calculated. The blood volume entering the microcirculatory system of the albino rat's mesenterium is distributed in the vessels as follows: 8,4% -- arterioles, 10,2% -- pericapillary arterioles, 41,9% -- capillaries, 22,1% -- postcapillary venules and 17,4% -- venules. Similar correlations were found in the cat. The working surface of capillaries is 60--70% of the working surface of all the vessels of the mesenterial microcirculatory system. The evidence of the functional variability of the microcirculatory bed geometry depending on the tissue needs in blood supply is presented.