THE OBSERVATION OF EMBRYONIC DEVELOPMENT OF SMALL INTESTINE IN CHINESE BY SEM AND LM STUDY / 解剖学报

ABSTRACT

The surface morphology and histogenesis of small intestine of human embryos (from 6 to 36 weeks) were studied by scanning electron microscopy and light microscopy. The results indicated that some low prominences began to form at 6 weeks of gestation and then transformed to round tuberculum, after that to polygonal column. The finger-like intestinal villi were formed finally at the end of 3 months. There was a apparent proximodistal gradient of the morphological maturation of villi and the histogenesis of intestine from duodenum, jejunum to ileum. Splitted and branched villi were found. From 18 weeks onward, the respective characteristics of villi in the three segments of small intestine appeared. Neutral mucus and sialomucus were mainly secreted by the goblet cells, while sulphomucus was secreted by the goblet cells of ileum during the late gestation. By 6-12 weeks the microvilli of duodenum were shorter than that of jejunum and ileum but they increased in height to 1.4?m at 18 weeks. The height of microvill at jejunum and ileum were 0.8-1.0?m from 14 weeks to 32 weeks. Tufts of thick and long microvilli among short microvilli were found. The formation of villi, secretion of goblet cells and microvilli was discussed.