| impermeable | Not permeable; not permitting the passage of substances (e.g., liquids, gases) or heat through a membrane or other structure. Synonym: impervious. Origin: L. Im-permeabilis, not to be passed through (05 Mar 2000) |
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| impermeable cell junctions | <cell biology> Specialised intercellular junction in which the two plasma membranes are separated by only 1-2nm. Found near the apical surface of cells in simple epithelia, forms a sealing gasket around the cell. Prevents fluid moving through the intercellular gap and the lateral diffusion of intrinsic membrane proteins between apical and baso lateral domains of the plasma membrane. (18 Nov 1997) |