What connects adjacent cells via electron-dense plaques on the cytoplasmic surfaces of the junctional membranes?

• A. Desmosomes
• B. Tight junctions
• C. Gap junctions
• D. Hemidesmosomes

Answer: (A)

Desmosomes are anchoring junctions that hold adjacent cells together under mechanical stress. They form electron-dense plaques on the cytoplasmic faces of the cell membranes and connect to intermediate filaments inside each cell through desmosomal cadherins (desmoglein and desmocollin). The cadherins on neighboring cells bind across the intercellular space, creating strong adhesion points that distribute tensile forces, which is why these junctions are abundant in tissues that undergo stretching, like skin and heart. In contrast, tight junctions seal but don’t link cytoskeletons across cells, gap junctions form channels for communication, and hemidesmosomes connect cells to the basement membrane rather than to other cells.