Combined intravital microscopy and electron microscopy of the blind beginnings of the mesenteric lymphatic capillaries of the rat mesentery. A preliminary report.

The blind beginnings (so-called terminal lymphatics) of the mesenteric lymphatic capillaries have been studied in the rat mesentery by means of intravital microscopy and electron microscopy. Intraluminal objects were observed to move slowly downstream, probably carried by the movement of the lymphatic fluid. No simultaneous changes in capillary lumen could be observed, and the subsequent electron microscope analysis of the same lymphatic capillary demonstrated the absence of smooth muscle cells in the wall of the lymphatic vessel. Interendothelial gaps were present, allowing the uptake of interstitial fluid into the blind ending of the lymphatic capillary.