Desmosomes. Transmission electron micrograph (TEM) of a section through epithelium containing two adhesion junctions or desmosomes (dark areas). Desmosomes form the most common type of junction between epithelial cells, providing points of adhesion. Dense plaques (black) are seen at the junction, lying immediately beneath the membranes. Fine fibres called tonofibrils extend from the plaques into the cell cytoplasm on either side of the junction. Desmosomes are frequently found in tissues such as skin that have to withstand mechanical stress.