paracellular pathway

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paracellular pathway The route between cells. For example, substances can travel through epithelia by a paracellular pathway if the tight junctions between constituent cells are not fully continuous (i.e. ‘leaky’), as in the proximal tubule of a kidney nephron. Paracellular pathways lack any means of active transport, and substances can only move passively by simple diffusion. Compare transcellular pathway.