[Ultrastructure of conducting and working myocytes in papillary muscles of the heart of intact rabbits].

The quantitative and qualitative ultrastructural analysis of specialized conducting and working myocytes in papillary muscles of the rabbit heart was made. The volume fractions of myofibers, mitochondria, nuclei, lipids, vacuoles, glycogen, sarcoplasmatic reticulum, T-tubules, lysosomes, and "clear" cytoplasm of conducting and working myocytes were estimated in addition to cell diameters. The results were compared with literature data for the Purkinje cells of different mammals. Principles of morphological description of conducting and working myocytes, allowing to recognize these cells in different parts of the heart and to compare them in different animals, are discussed.