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EXPERIMENTAL FIGURE 20-19 Tight junctions prevent passage of large molecules through extracellular spaces between epithelial cells. Tight junctions in the pancreas are impermeable to the large water-soluble colloid lanthanum hydroxide (dark stain) administered from the basolateral side of the epithelium.
[©1972, Friend, D. S. and Gilula, N. B., J. Cell Biol. 53(3):758–776.]