초록
The morphological studies on the rectal development in the 60-, 90- and 120-day-old fetuses and neonates of Korean native goats were investigated by light microscopy and scanning electron microscopy. The rectal wall appeared to be differentiated into the epithelium, lamina propria, tunica muscularis and serosa in 60-day-old fetus. The rectal epithelia were stratified in some areas and simple columnar in others at 60- and 90-day-old fetuses but was only observed simple columnar epithelium at 120-day-old fetus. The goblet cells and the intestinal glands appeared in the rectal mucosa at 90-day-old fetus and gradually increase in number during gestation period. The rectal villi appeared at 60-day-old fetus and increased in length and width until 90-day-old fetus but the villi appeared to be shorter and degenerated after 120-day-old fetus. Only the rudiment trace of the villi remained at birth. The tunica muscularis of the rectum were continuously developed during gestation period. The inner circular and outer longitudinal muscle layers of rectum were observed in the 120-day-old fetuses. Under scanning electron microsoopy, the rectal villi appeared at 60-day-old fetus. The pentagonal/hexagonal microridges and numerous microvilli were observed on the luminal surface of rectal wall. Low and thumb-like rectal villi were developed at 90-day-old fetus. The rectal villi became degenerated after 120-day-old fetus. Only the rudiment of villi was remained at birth. Many circular folds were well developed. Opening portions of intestinal glands appeared like slot.
