THE ULTRASTRUCTURE OF THE ADULTS' A-V BUNDLE, PSEUDOCHORDAE TENDINEAE AND MODERATOR BAND / 解剖学报

ABSTRACT

The specimens were taken from two adults' hearts, thirty-four and twenty-eight years of age respectively. The A-V bundle was taken from the middle part of postero-inferior edge of the membranous part of the ventricular septum. The moderator band were cut from its superficial and deep part. The pseudochordae tendineae were collected from the left ventricle. All of the samples were fixed by 4％ glutaraldehyde. The chief results were as followsThere are many Purkinje cells in the A-V bundle, moderator band and pseudochordae tendineae. The shape of the Purkinje cells is broader and shorter than the ordinary myocardial cells. The myofibrils and myofiliments of the Purkinje cells are less than of those of the ordinary myocardial cells. The mitochondria of the Purkinje cells were often situated around the nucleus. In the A-V bundle, a few transitional cells and general myocardial cells may be observed. Therefore the His bundle may be consisted of Purkinje cells transitional cells and a few general myocardial cells. Our findings are not in accordance with that of Glomset et al. They observed that the A-V bundle only consisted of the general ventricle myocardial cells. The intercalated discs present between the Purkinje ceils in the A-V bundle were not typical. Besides the intercalated discs, we observed two sorts of the junction types in the A-V bundle (1) An intercalated disc was observed between a branch of a transitional cell and the lateral surface of the other adjacent transitional cell. (2) Through the collagenous septum, there was a junction between a transverse branch of transitional cell and opposite transitional cell.