[Quantitative electron microscopic analysis of tissue components of the subendocardial region of the dog heart].

Quantity and distribution of Purkinje conducting cells, contractile cardiomyocytes, connective tissue, capillaries and nervous structures in the conducting and working myocardium (CM and WM) of the subendocardial area of the anterior papillary muscles of the dog heart were studied. Predominance of the contractile cardiomyocytes volume density over that of Purkinje cells and a higher level of the volume density of capillaries and nervous structures were characteristic of WM comparing to CM while the connective tissue volume density was higher in CM than in WM. These variations in the distribution and quantitative content of tissue structures may determine the primary damage of the subendocardium as well as non-similar response of different animals to the same impact.