The ultrastructural basis of lipid transport in the absorbing lymphatic vessel.

Absorbing lymphatic vessels of intestinal villi were studied by electron microscopy tridimensional reconstruction in order to follow the passage of lipid from the interstitium into the capillary lumen. The duodenum and ileum of kittens after milk feeding, fasting and lymphatic stasis were investigated. Lipids reach the lymphatic system by intraendothelial 8-14 micrometers long channels, which are directed from the apical to the basal portion of the lacteals. Endothelial junctions were always intact, indicating that these complexes were not involved in the transport of large size molecules.