人窦房结的内部构筑

THE INTERNAL ARCHITECTURE OF HUMAN SINOATRIAL NODE

用组织学连续切片方法,在15例人心窦房结标本上(7例成人,8例胎儿)分别观察窦房结的位置,形态和内部纤维构筑。人窦房结可分为4层,从内到外分别为: 1.窦房结动脉层;该动脉的结内段有的部分缺乏纵行肌; 2.动脉周围层:此层细胞呈环形围绕结动脉; 3.中央层:该层P细胞束沿着窦房结动脉平行排列,并组成结的大部分,其细胞直径在成人为5.18μm;4.外周层:此层移行细胞的大部分呈现从窦房结放射排列进入心房肌的趋势,大部分“移行细胞舌”伸入到右侧心房肌,但很少伸入到上腔静脉侧。该层移行细胞在成人直径为7.28μm。在成人胶原纤维的排列方向有内环、中纵、外放射的排列现象。本文就窦房结的内部构筑讨论了其功能意义及窦房结折返的形态学基础。

The location, shape and internal architecture of the sinoatrial node (SAN) were studied histologically in serial section in 15 hearts (7 adults, 8 foetuses). Based on our observation, the human SAN may be divided into four layers, namely, (1) thesinoatrial node artery layer: its outer longitudinal muscular layer of its media partly lacked in the SAN concentrically; (2) the periarterial layer: the cells of this layer surround the artery concentrically; (3) the central layer, making up the main mass of the node: most P cells in which are arranged parallel to the node artery. In adult the diameter of P cells in this layer is 5.18 μm; (4) the peripheral layer: most transitional cells in this layer radiate from SAN into the atrial muscle. These 'tongues of transitional cells' extend mostly into right atrial-muscle and a few into the musculature of superior vena cava. The diameter of transitional cells of this layer in the adult is 7.28 μm. In the adult the arrangement of dense collagen fibers appears circular in the periarterial layer, longitudinal in the central layer and radiative in the peripheral layer. According to the location, layers of sinoatrial node and the arrangement of the connective tissue, the functional significance and morphological basis of the re-entry are discussed.