目的 观察和分析12只中华鳖脾脏椭球的显微和亚显微结构,阐明其循环特点. 方法 应用光镜和透射电镜技术,结合心脏注射墨水悬液方法,显示脾脏椭球的组成、结构与循环. 结果 中华鳖脾脏白髓由动脉周围淋巴鞘(PALS)和椭球周围淋巴鞘(PELS)两种结构组成,缺乏淋巴小结.红髓包括脾索和脾窦,未发现边缘区.中央微动脉穿出PALS后,呈笔毛状分成数条椭球毛细血管,后者周围由PELS包绕.椭球毛细血管的末端直接开口于红髓的脾索,血流注入脾索,而后穿过脾窦内皮间隙进入脾窦.不同于普通血管内皮,椭球毛细血管内皮一般为立方状,基膜不完整,其外即为椭球结构.椭球壁由支持细胞、椭球相关细胞和网状纤维等构成.常见淋巴细胞和红细胞穿过椭球壁.注射墨水悬浮液后40min,可见整段椭球壁上分布着大量墨水碳粒. 结论 中华鳖脾脏椭球毛细血管相当于哺乳动物的高内皮后微静脉,是淋巴细胞和血细胞进出淋巴组织的重要通道.中华鳖脾脏循环属于开放式循环“,”Objective To examin and analyze the structure, ultrastructure and the circulation of the spleen ellipsoid in the soft-shelled turtle, Pelodiseus sinensis. Methods Twelve turtles were used and observed by light- and electron-microscopy and injection of ink suspension in this study. Results The spleen white pulp was consisted of the periarteriolar lymphatic sheath (PALS) and periellipsoidial lymphatic sheath (PELS). There was no lymphoid nodule in the spleen. Red pulp included splenic cords and splenic sinusoids. The marginal zone was not found in the turtle spleen. When the central arteriole left out of the PALS, it divided into several ellipsoid capillaries which were surround by the PELS. The end of the ellipsoid capillary opened directly to the splenic cord and the blood cells then entered into the splenic sinusoid through the gap between the endothelial cells. The ellipsoid capillary was consisted of simple cuboidal epithelium with an uncompleted basement membrane. The ellipsoid wall was consisted of supporting cells,ellipsoid-associated cells and reticular fibres. Lymphocytes and red cells were always found on the ellipsoid wall. After 40min of the injection of ink suspesion, much carbon particles of ink were restricted on the wall. Conclusion The ellipsoid capillary in the soft-shelled turtle, just like the high endothelial venule, was the important passage of the lymphocytes and blood cells going out and into the lymph tissue. The splenic circulation in the turtle belongs to the opening model.