Junctional complex between two adjacent epithelial cells in the lining of the small intestines.

1 = Tight junction (zonula occludens) in which the outer leaflets of the plasma membranes have fused

2 = Intermediate junction (zonula adherens) in which the plasma membranes are separated by a space of approximately 200 Å (20nm)

3 = Desmosome (Macula Adherens) in which cell membranes are again separated by about 200 Å (20nm), but the inter-cellular space contains electron-dense material. Within the cytoplasm of each cell there is a dense plate-like structure (see arrow).

To the right are microvilli lining the luminal surface of the cells. The trilaminar appearance of the plasma membrane (2 thin, dark lines with pale in between) covering each microvillus can be seen clearly in several places. Notice also the microfilaments extending from the bases of the microvilli, into the terminal web area of the cell cytoplasm.

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