胎儿房室结微血管构筑的扫描电镜观察

用血管铸型结合扫描电镜方法观察了7例胎儿房室结微血管构筑.微动脉反复分支呈树状,行走方式呈波浪形或螺旋形.毛细血管网可分为内外两层:外层纵行为主,以"H"或"Y"形吻合;内层弯曲行走为主,并互相交错吻合.以房室结动脉主干为界,其下方毛细血管密度较大,其上方及前方较小.房室结的上方、前下方和后下方均有微动脉连接毛细血管网.整个结的毛细血管大致可分为结后部上方、下方及前部三个区域.靠毛细血管网外层处可见管径较粗、呈袋状的微静脉.

OBSERVATION ON MICROVASCULAR ARCHITECTURE OF ATRIOVENTRICULAR NODE IN FETUS BY SCANNING ELECTRON MICROSCOPY

The microvascular architecture of atrioventricular nodes in seven fetuses was observed by means of vascular casts and scanning electron microscopy.The arterioles,continuously branching out in the shape of the tree,were distributed in the pattern of wave or spiral.The capillary network was divided into an external layer and an internal layer.The capillaries in the external layer were mainly longitudinal,their anastomoses in the shape of the letter 'H' or 'Y'; the capillaries in the internal layer were mainly crooked and connected with each other.The capillary density in the lower part of the main trunk of the atrioventricular node artery was greater than that in the upper and anterior parts.The capillary network in the node,connected by the arterioles from the superior,lower-anterior and lower-posterior parts of the node,was approximately divided into an upper-posterior area,a lower-posterior area and an anterior area.The thicker and pocket-like venules were found near the external layer of the capillary network.