【摘要】 目的 :探讨房室结双径传导的形态学基础。方法 :选用家兔 10只 ,分别做房室隔的水平面和额状面的连续切片 ,光镜下观察其组织形态学特征。结果 :1房室结 (AVN)由形态结构不同的 3层细胞组成 ,浅层细薄 ,由普通房肌细胞和过渡细胞 (TC)组成 ,波浪形疏松平行排列 ;中层较厚 ,排列致密且交织成网 ,由 TC和起搏细胞 (PC)组成 ;深层肌纤维较粗且有交错 ,由 TC和 PC组成 ;3层均以 TC为主。 2 AVN后方可见一大束疏松排列的过渡细胞束 ,为结后延伸 (PNE)。3房室交界区心房扩展部可见 4条主要由 TC构成的房结束 (ANB)。它们分别走行于 AVN的右下方 ,右后方 ,左方和上方。4 AVN ,PNE,ANB均主要由 TC构成 ,而 TC直径小于普通房肌细胞。结论 :1AVN浅层的传导速度可能快于中、深层。 2 ANB、PNE可能为房室结双径中的慢径提供了形态学基础更多还原

【Abstract】 AIM: To investigate the morphological basis underlying dual atrioventricular nodal pathways(DAVNP) of conduction. METHODS: The histological features of the atrioventricular septum of ten rabbits were observed under light microscope by means of serial sections. RESULTS: ①AVN was composed of three layers of cells with different structures. The superficial layer was slender and parallelly arranged. It was mostly composed of transitional cells(TC) besides a few ordinary atrial myocytes. The middle layer was tightly packed and interlocked. The deep layer was interlocked. The middle and deep layers were mostly composed of TC besides some pacing cells. ② A posterior nodal extension (PNE), which was composed of a large transitional cellular bundle was found in all preparations studied and linked forward to AV node.③At the atrial extension part, four transitional cellular bundles were found linked forward with PNE or AVN respectively from the right inferior, right posterior, left and superior of AVN. We called them atrial nodal bundle(ANB).④Similarly AVN, PNE and ANB were also mostly composed of TC. The diameter of TC was smaller than that of the ordinary atrial myocyte. CONCLUSION: ①The conduction velocities of the superficial layer of AV node may be greater than those of the middle and deep layers. ②ANB and PNE may provide the morphological basis for the slow pathways of DAVNP.更多还原