The three categories of cell-cell junctions are:
Tight junctions: These junctions are formed by the fusion of plasma membranes of adjacent cells, and prevent the movement of molecules between the cells. They are found in tissues that need to maintain a barrier function, such as the lining of the intestine.
Desmosomes: These junctions anchor adjacent cells together, and are found in tissues that experience mechanical stress, such as skin and heart muscle.
Gap junctions: These junctions allow for the direct transfer of small molecules and ions between adjacent cells, and are found in tissues that require rapid communication, such as in nerve and muscle tissue.
~~~Harsha~~~