Abstract: | The myocardium of 20 Citellus erythrogenys Br. was studied by quantitative morphology in different seasons. Morphometry and stereological methods were used to measure the cardiomyocyte diameter, volume and surface densities of the main tissue structures. The morphological criteria were derived for the seasonal features of the relations in muscular and connective tissues of the hibernating rodent myocardium. Myocardial atrophy (seasonal regression of the heart weight and the cardiomyocyte diameter) was noted during hibernation. It was accompanied by adaptive tissue reorganization. The parenchymal-stromal relations in the myocardium of both active and hibernating animals were found to be stable. In these conditions there occurred significant changes in the architectonics of the myocardium. |