用透射电镜观察了28例8～28周人胚胎小肠APUD细胞,发现在胚胎发育第8周肠上皮的基底层即可见到APUD细胞,早于以往文献报道.根据细胞的形态和分泌颗粒的形状大小,在胚胎的不同时期观察到7种APUD细胞,即:EC细胞(Ec1、Ec2、Ecn)D1细胞,D细胞,S细胞,I细胞,P细胞和K细胞.在胚胎发育第20周时观察到少量开放型的Ec细胞,提示其在发育中负有重要生理功能. Transmission electron microscopy was used to observe APUD cells in 28 cases of human embryonic small intestine from 8 to 28 weeks and found APUD cells were seen in the basal layer of the intestinal epithelium at the 8th week of embryo development as earlier reported in the literature.According to the morphology of the cells and the shape of the secreted granules Seven APUD cells, namely EC cells (Ec1, Ec2, Ecn) D1 cells, D cells, S cells, I cells, P cells and K cells were observed at different stages of the embryo. At the 20th week of embryo development A small number of open Ec cells were observed, suggesting that they have important physiological functions during development.