成人心传导系统的超微结构

目的　进一步观察成人心传导系统的超微结构。方法　对窦房结、房室结采用纵切法 ,分别于其头、体、尾部切取 1mm3 组织各两块 ;房室束分叉部采用横切法切取其分叉部的近、远段组织各两块 ,用透射电镜观察。结果　 (1)窦房结头部或头体交界部见P细胞 3～ 4个环抱成团 ,团内细胞互相广泛连接 ,构成一个电传导装置 ;(2 )窦房结和房室结可见有功能下降的明细胞与代偿性功能增强的暗细胞相并列 ;(3)结细胞退行性变与纤维组织增生并举 ;(4)窦房结的退行性变化从外侧部、尾部开始。结论　推测窦房结的头部和头体交界部可能是窦房结的起搏中心

The ultrastructure of the cardiac conduction system in adult human

Objective To investigate the ultrastructure of the cardiac conduction system in adult persons.Method Longitudinal sections of the sino atrial node and the atrio ventricular node of 4 adult persons,two pieces(1mm 3)of tissues each from the head,body and tail area,and transverse sections of the proximal and distal parts of the bifurcation of His bundle were observed under transmission electronic microscope.Results (1)Clusters of three to four P cells showed broad connections between the cells and thus formed eletro conduction apparatus.(2)Light cells of dysfunction and dark cells of intensifyiing function could be seen in the sino atrial node and the atrio ventricular node.(3)Retrogression of the nodal cell and the proliferation of fibrous tissue occur synchronismly in the cardiac conduction system.(4)The retrogression in the sino atrial node occur originally from the outside and tail area.Conclusion The head or the connecting area between the head and body areas might be the pacemaker.