RESUMEN
Objective Observe the fine distribution and morphologic feature of the intramural lymphatics in rats' rectum and to provide the morphological evidence for studying the mechanism of lymphous metastasis of rectum carcinoma.Methods The intramural lymphatics of rectum in rats were studied by light and electron microscopy to obtain some data regarding their fine distribution.Results The intramural capillary lymphatics of rats' rectum were observed in deep lamina propria of tunica membrane and the dermal papilla layer of anal pectin. The intramural capillary lymphatics and lymphatics were both observed in tela submucosa, reticular layer, hypodermis and intermuscular and serosa. The capillary lymphatics in rectums' wall have the similar ultrastructure feature to normal ones. Three kinds of endothelial cells junctions are overlapping-junctions, embedding-junctions and end-to-end-type junctions. About 21% of cell-junctions are opening types. There are normal organelles and many vesicals in the endothelial of capillary lymphatics. Conclusion The distribution of lymphatics in every layer of dentate line upwards are similar to other digestive tubes'. The distribution of lymphatics in anal pecten of rats' rectum are similar to cutis. The results show that big molecule substance and tissue hydrolysate are transporting mainly by opening-junction of endothelial cells and the vesicle system.