Introduction
Cells are independent units of life. However, when a cell becomes part of an organism, it becomes part of a tissue and organ system. Cells in a tissue are joined to each other and to the extracellular matrix (ECM) by cell junctions. There are three kinds of cell junctions: Occluding junctions, anchoring junctions and communication junctions. Occluding junctions occur in the epithelium where the adjacent cells are so tightly sealed together that even small molecules cannot pass. Communicating junctions allow the exchange of chemical and electrical signals between cells. Anchoring junctions are the ones which attach a cell either to its neighbor or ...
