从北京鸭的个体发育看肝的组织结构

THE STRUCTURE OE THE LIVER IN THE EINBRYONIC DEVELOPMENT OF THE PEKING DUCK,anas domesticus

引言肝是动物的重要代谢器官,早在17世纪 Wepfer(1664),Malpighi(1666)等对于它的组织结构已有了初步认识。到了19世纪和20世纪初叶,许多学者对于肝的显微结构作了细致的观察,对于肝细胞排列的形式解释虽不尽相同,但认为组成肝实质的细胞排列成索状或小管状却是一致的意见。那些弯曲的肝细胞索或肝小管围绕着中央静脉作辐射状排列。

The development of the Iiver primordia and the differentiation of the Iiver parenchyma are studied in a series of duekliugs from 30 hours of incubation to 7 days after hatching.The two endodermal diverticula originate simultaneously from the margin of the anterior intestinal portal near the juncture of the omphalomesen- teric veins in some 20 semite embryos(F.1).The posterior hepatic diverticulum is observed to branch into right and-left buds in a number of embryos with 25-26 omites(F.3),and the anterior diverticulum branches later in the embryos approxi- mately 32-33 somites(F.8).The liver diverticula grow cephalad into the mesenchyma of the ventral mesntery,the anterior diverticulum dorsal and the posterior ventral to the ductus venosus(F.7-10).Both diverticula proliferate solid and luminated buds which form a network surrounding immediate portion of the ductus venosus.An invasion of the lumen of the ductus venosus by the hepatic tissue ocurrs at 90 hours of incubation(F.12).The appearance and the differentiatlon of the hepatic tissue in the duck do not occur later than those in the chick,in spite of the fact that the incubation period is much longer for the former.