人胎儿腓肠神经结旁环中的膜下池和环间桥粒串  

HYPOLEMMAL CISTERN WITH IN PERINODAL LOOPS AND DESMOSOME STRINGS BETWEEN THE LOOPS OF PERIPHERAL NERVES IN HUMAN FETUS

作　　者：卢戈[1] 

机构地区：[1]兰州医学院组织学胚胎学教研室,兰州730000

出　　处：《动物学报》1993年第4期362-367,共6页ACTA ZOOLOGICA SINICA

摘　　要：电镜下对22例水囊引产或手术取出之4-足月胎儿腓肠神经进行了观察研究,特别注意了朗飞结的结构,观察到:1.一般特征:髓鞘较成体的薄;轴索的裸区较成体的长;结旁环间轴索侧有紧密连接,将环间间隙和轴索周间隙分开;结旁环的顶部与轴索压迹之间有致密突起将二者相连,在其两侧的细胞膜下均有致密层物质。2.结旁环中有膜下池;每个环中有一个,位近顶部膜下,断面呈圆或椭圆形,排成一排。在切线切面可见这些膜下池实际是呈串珠状膨大的滑面内质网。一般其内容物呈中等电子密度;在某些病理因素影响下,池扩张,内容物密度很低而呈白色。3.结旁环间桥粒:位于(1)外轴系膜的起始部,沿系膜纵行开口处间断或连续分布;(2)近裸区的结旁环间形成较大的弓形桥粒串;(3)在髓鞘刚散开的结旁环间,形成较小的弓形桥粒串;(4)中部结旁环间有散在或成串的桥粒;(5)在短肢畸型病例中,结旁环较薄,环间桥粒串较多。讨论了轴膜周间隙与结旁环间间隙间紧密连接、结旁环中膜下池及结旁环间桥粒的可能功能。The sural nerves of 22 human fetuses aging from the 4th month to full term were observed under transmission electron microscope, and the attention was particularly paid to the ultrastruc-ture of the nodes of Ranvier(NR). It was found that: 1. The general feature--The myelinsheaths of the fetuses were thinner than those of the adults . The naked area of axon at NR in the fetuses was longer than that of the adults. There were tight junctions between the perinodal loops adjoining axon, which separated the periaxonal spaces from the spaces between the loops. The top of perinodal loop was connected with the axolemma on its opposite by the dense process, and there was the dense layer substance this site under both cellular membranes; 2. The hypolemmal cistern within the perinodal loop. Under the callular membrane at the top of each loop, there was a cistern, round or ovoid in shape. In the tangential sections, these hypolemmal cisterns were practically the smooth endoplasmic reticula with beads-like expansions. The contents generally showed a moderate electron density but under some pathological conditions,the cisterns dilated and the density of contents became very thin and showed a light stain; 3. The desmosomes and desmosome strings between the perinodal loops, (1)In the starting part of the outer mesaxon, there were the desmosomes longitudinally distributed in series or at intervals along the opening of mesaxon; (2)Between the perinodal loops near the naked area, there was a big arched string of desmosomes; (3)Between the perinodal loops where the myelin sheath began to disperse, there was a small arched string of desmosomes; (4)There were the scattering desmosomes or the desmosome strings; (5)In a case of short limb malformation,the perinodal loops were thinner, there were more desmosome strings between the loops. The probable functions of the tight junction between the periaxonal space and the space between the perinodal loops, of the hypolemmal cisterns within the perinodal loops,and of the desmosomes and desmos

关 键 词：人 胎儿 腓肠神经 膜下池 桥粒串 

分 类 号：R329.1[医药卫生—人体解剖和组织胚胎学]