occluding junction

Tight junctions (occluding junctions)

By contrast, a true epithelial tissue is present only in a single layer of cells held together via occluding junctions called tight junctions, to create a selectively permeable barrier.

In cultured human intestinal epithelial cell monolayers, the transepithelial resistance fell and the macromolecular permeability increased parallel to the numbers of polymorphonuclear leukocytes that migrated through intercellular occluding junctions.

However, they do have a sheath of perineurial glial cells that envelops the nervous system and exhibit the same tight occluding junctions that are induced by the glia limitans in humans.