Zagoruiko G. E., Martsinovsky V. P., Zagoruiko Yu. V., Filatova V. L., Shmulich O. V.

BIOLOGY

Scentific article

Absract. The presented data of morphometric studies indicate that in the process of postnatal maturation of CMC, in the time interval (n-b – 45) days, the length of the CMC increases from 25 (n-b) to 81 ± 5 μm, the crosssectional diameter of myocytes increases from 9.1 (n-b) up to 15.3 ± 0.5 μm. The values of the L / D index increase from 2.75 (n-b) to 5.3 by 45 days. The complex folded and convoluted shape of the CMC surface in newborn rat pups gradually straightens out during postnatal ontogenesis. The most active process of straightening (smoothing) sarcolemma CMC and an increase in its surface area observed within 30 days after birth of rat pups. This is due to the intensive growth at the beginning of the longitudinal size and then the transverse size of the cardiac left ventricular cardiac muscle. By the 30-th day after birth of rat pups, the formation of intercalated discs ends. The presented data indicates that at t ≥ 30 days, the approximation of the spatial form of the 2c-CMC LV by a circular cylinder is quite justified and allows us to determine the values of the real surface area of CMC according to the approximate formula Scmc(r) ≈ Scmc x k. In this formula: Scmc – total surface area of a circular cylinder, k ≈ 1.2. The criterion for the optimality of the approximation Scmc → Scmc(r) is the index k = Svcmc(r) / Svcmc. The Svcmc(r) values are determined by the “random secant combined with the point method” method. Svcmc is the specific surface area of a CMC in the form of a cylinder. At t ≥ 30 days, the approximation of the CMC is shaped by a circular cylinder allows the values of Scmc(r) to be determined with sufficient accuracy using the coefficient k. The proposed method for determining the values of Scmc(r) is simple in the objectivity, clarity and simplicity of the computational procedures.

cardiogenesis, cardiomyocyte, morphometry, approximation.

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«Bulletin of problems biology and medicine» Issue 1 (159), 2021 year, 134-138 pages, index UDK 576.311.347:611.127-018

10.29254/2077-4214-2021-1-159-134-138