T hese epithelial cells have very strong adhesion. This quality of intercellular adhesion is especially prominent in epithelial tissues which are normally subjected to traction and pressure. Why are these epithelial cells so cohesive and strong that they are not separated but connected to each other to form various organs? Because along the boundary of adjacent epithelial cells there is a system of cell junctions between the epithelial cells (Uunctional complex). This system will be discussed at this writing. Where there are three types of cell links, namely impermeable junctions or occluded zonules, the second is adhering junctions or zonulas and the third is fractured junctions or nexus and there are also types of links called desmosomes or maku/a adherens and hemidesmosomes. All linkage systems in epithelial cells, especially in the mucous membranes of the mouth, will be discussed in the next chapter.