Tight junctions are found in cells that are fused together and they do not allow any substance to traverse cells. They are found in distal convoluted tubule, collecting duct of the nephron in the kidney, bile ducts and blood brain barrier.
Gap junctions allow exchange of substances between adjacent cells. They are found in nerves, cardiac muscle, intestines and skin cells.
Desmosomes help cells to adhere to the extracellular matrix (ECM) with the help of proteins. These are present in myocardium and epidermis.
Interdigitations increase surface area and hence contact between cells.