MORPHOLOGICAL FEATURES OF THE RED FOX HEART (Vulpes Linnaeus, 1758)

Abstract

A comprehensive and in–depth study of the structure and morphofunctional justification of the work of the heart is always relevant, since the heart ensures constant blood circulation in the body, supplying cells with oxygen and nutrients, as well as removing metabolic products. The heart is the most important element of the cardiovascular system of humans and animals, and even minor disturbances in its work can lead to serious pathologies. The purpose of the research was to find out the morphological structure and morphometric features of the heart (linear parameters, morphometry of the ventricles and atria, cytometric indicators of cardiomyocytes) in the common fox (Vulpes Linnaeus, 1758) in a comparative species aspect. On the basis of morphological and morphometric research methods, new data on the macro– and histological structure of the heart and its cytomorphometric characteristics of morphological structures in healthy vertebrates (n=5), class Mammalia – mammals, common fox – Vulpes Linnaeus, 1758 are presented. According to the results of organometry (height – 6.52±0.19 cm, width – 4.42±0.02 cm, circumference – 11.8±0.27 cm), the heart of the common fox is expanded–shortened, elliptical in shape, as evidenced by the index of its development – 147±3.76%. The most developed morphological structures of the heart are the right and left ventricles, followed by the right and left atria, which correlates with the linear parameters of the thickness of their walls: the wall thickness of the left ventricle is significantly (p≤0.001) 3.23 times greater than that of the right ventricle, respectively, the wall thickness of the left atrium is reliably (p≤0.05) greater than the wall thickness of the right atrium 1.4 times. The absolute heart weight of a sexually mature fox is 40.6±1.96 g, relative – 0.46±0.015 %. The net weight (without epicardial fat) of the heart is 38.2±1.85 g, corresponding to 0.43+0.01% of the total weight of the animals. Under such parameters, left ventricular AM is the largest (52.06±0.591%) and equal to 19.78±0.48 g, right ventricular AM (26.12±0.742 %) is two times smaller and is 9.92±0.42 g. At the same time, the absolute weight of the LV and LV of the heart together (78.18±0.865 %) is 29.72±0.54 g. Atrial AM is significantly smaller: LP – 5.88±0.3 g (15.5±0.163 0.25%), PP – 2.40±0.18 g (6.32±0.203%). The total absolute mass of the right and left atria (21.82±0.289 %) is 8,3±0,138 g. At the same time, the coefficient of the ratio of ventricular AM to net heart weight is 1:0.78, the coefficient of the ratio of atrial AM to net heart weight is 1:0.22, and the coefficient of the ratio of atrial AM to ventricular AM is 1:0.28. The histological structure of the myocardium of the heart of the ventricles and atria is formed by cardiac striated muscle tissue, the main structural elements of which are contractile cardiomyocytes that form a network of pore striated, different in thickness muscle fibers. According to cytometry results, left ventricular cardiomyocytes are larger in size: their length is significantly (p≤0.05) greater than the corresponding figures of the right ventricle by 1.28 times, and the width of left ventricular cardiomyocytes is greater by 1.13 times. At the same time, LV myocardial cardiomyocytes have the largest volume – 7602.32±78.38 μm3, smaller – RV (4728.02±114.25 μm3) and, the smallest – atrial cardiomyocytes – 3424.50–69.84 μm3. According to such indicators, the coefficient of the nuclear–cytoplasmic ratio is different: the least characteristic of LV cardiomyocytes is 0.0277±0.01627, significantly (p≤0.01) more – for LV cardiomyocytes – 0.0419±0.02307) and reliably (p≤0.001) the most for atrial cardiomyocytes – 0.0498±0.03444, which is related to the features of the muscle woven myocardium capable of spontaneous rhythmic contractions.