Abstract
As part of a series of morphological studies on the heart beat and blood vascular phenomenon in the vertebrated animals, the authors investigated silver-blackened fibers distributed in the blood vascular system. As a result, detailed descriptions were made on the very complicated architectonic of these fibers distributed in the cardiac muscle, the relationship between these fibers and the endothelial cells of blood capillaries, and the presence of some correlations between these fibers and erythrocytes.
The following conclusions were drawn from the present investigation.
1. A complicated secondary node (an auxiliary node, an atrioauricular relay node) was recognized to exist between the node of silver-blackened fibers so far known and the main trunk of these fibers.
2. It was indicated that there was an atrioventricular border node on the boun dary between the atrium and the ventricle in the heart of eel.
3. The terminal branches of the peripheral divisions of these fibers distributed in the atrial and ventricular portions of the heart formed a spiral structure, a close contact with the sarcolemma, ramifying endings, and terminal networks.
4. In the walls of blood capillaries, silver-blackened fibers are distributed in the area where the basement membrane of the endothelial cells is located. They show a close relationship to the endothelial cells. The adventitial cells are present external to these fibers, there being only a weak direct relationship between these cells and fibers.
5. It seemed that the erythrocyte played a very important part in the activation and regeneration of silver-blackened fibers. This presumption was made from the observation on the destruction phenomenon of erythrocytes.
Therefore, formation of a node (a secondary node) by silver-blackened fibers, the state of termination of terminal branches, distribution of these fibers in the walls of blood capillaries, and the correlations between these fibers and erythrocytes were clarified in the present investigation. From the results obtained with regard to the distribution and construction of these fibers, it is advocated that these fibers are very closely related to the heart beat and blood vascular phenomenon.
