Oviductal lymphatics and their relations with the paraovarian lymphatic plexus in the pig.

The lymphatic vessels emanating from the oviductal infundibulum, ampulla and isthmus were examined in the pig paraovarian sac and broad ligament walls to determine their relations with paraovarian lymphatic plexus. To differentiate the oviductal, ovarian and uterine lymphatic pathways injections of the three-coloured microfil were used. The precollector lymphatics in the paraovarian sac mesosalpinx created two networks running independently pathways towards the lymph nodes. A large multimesh network from the oviductal isthmus, especially in the late follicular and early luteal phases, together with uterine precollectors made the lymphatic plexus in subovarian areas. Both of these lymphatic networks did not possess direct connections for the lymph flow. The lymphatic system in the supraovarian sac was not evident scanty.

Morphological features of lymphatic and mesothelial communications in the broad ligament of the pig.

The broad ligament containing uterine, paraovarian, and oviduct lymphatics was examined in the pig in various phases of the estrous cycle using light, scanning and transmission electron microscopy. The architecture of these regions differed and was independent of the lymphangions of the precollector and collector lymphatic vessels. Lymphangions were separated from mesothelium by connective tissue and/or muscle layers; however, in the vicinity of the thin walled paraovarian sac, large lymphangions were often compressed between two epithelial layers. Numerous lymphatic lacunae were in direct contact with the peritoneal and paraovarian sac cavities. The mesothelial lining of the broad ligament and the external and internal epithelium of the pig paraovarian sac displayed two distinct cell types. Only smaller cuboidal cells with prominent microvilli extended above the lymphatic endothelium. The surfaces of these cells were discontinuous and showed: 1) lymphatic stomata, 2) small pores or fenestrae, 3) a superficial network of epithelial-free communications with underlying connective tissue to the paraovarian sac in the postovulatory period independent of the lymphatic vasculature, and 4) endothelial (instead of epithelial) cells with crevice-like discontinuities in large portions of the internal sac surface during the follicular phase of estrus. Numerous lymphatic stomata had orifices composed of flattened cuboidal cells while lymphatic endothelial cells were characterized by macula or zonula adherent connections formed within rims of various sizes (up to 50 microns in diameter). During estrus, there were circular (0.5-2.0 microns) and irregular (to 10 microns) interendothelial openings in stomatal orifices with migrating cells. These morphologic findings suggest that absorption and passage of fluid, particles and cells between cavities and the lymphatic lumen in areas of the paraovarian lymphatic plexus in the pig is feasible.

The presence of lymphatic stomata in the ovarian bursa on the European beaver as shown by scanning electron microscopy study.

The internal and external epithelial sheets of the ovarian bursa in the European Beaver were examined using scanning electron microscopy. Two types of epithelial cells were found on both surfaces, but only in the areas of the cuboidl cells were the lymphatic stomatae created. This suggests that the absorption and passage of fluid, particles and cells between the peritoneal and ovarian bursa cavities and lymphatic lumen in the beaver are possible.