Long description

This figure shows a schematic diagram which illustrates the three main types of cell junctions. The schematic shows three rectangular cells, with finger-like projections on the upper edge, lying in close proximity and above the basal membrane. From left to right, the cells are labelled cell 1, cell 2 and cell 3, and there are three types of junctions joining the cells together. Cell 1 is attached to cell 2 by an anchoring junction placed in the middle between both cells, holding the two cell membranes close together. This junction is labelled ‘anchoring junctions: important for structural support, particularly in tissues with a lot of movement/friction’. The cells are anchored to one another by a bundle of tubular cytoskeletal structures and extracellular matrix components. Cell 1 is also attached to cell 2 by a tight junction labelled ‘tight junctions: form a seal between two cells that prevents movement of water and other small molecules’. An intercellular barrier between two neighbouring adjacent cells has intercellular spaces between protein complexes and connects two cells tightly forming a fluid-tight seal. Cells 2 and 3 are attached by a gap junction placed near the basal membrane. This junction is labelled ‘gap junctions: cells are connected by channels that allow the passage of small substances between the cells’. The cell junction is formed by an intercellular bridge (fluid-filled protein channels) formed between adjacent cell membranes of neighbouring cells.