Cell to cell contacts are necessary for any higher organisation of cells and provide the basis for the formation of tissues and organs. In epithelia, sheets of cells are formed by close attachment of cells to each other, which is facilitated by cell adhesion molecules and further stabilised and differentiated by formation of specialised cell junctions. In multiple epithelia, cells are attached to each other by junctional complexes, composed of a characteristic combination of occluding and adhering junctions that regulate paracellular traffic and stabilise the tissue. Junctional complexes are symmetrical structures formed between adjacent cells and consist of three components: Firstly, a band of tight junctions, forming an occluding zone in the top position (zonula occludens, ZO, cf. also Fig. 84), secondly, a band of anchoring junctions in the middle position (belt desmosome, zonula adhaerens, ZA), and thirdly, a circle of spot desmosomes in the bottom position (maculae adhaerentes, MA, cf. also Fig. 86).