What is the function of desmosomes in epithelial tissue, and what type of filaments do they connect?

• A. Provide strong intercellular adhesion by linking intermediate filaments between cells; confer mechanical strength.
• B. Tight sealing between cells; link to actin.
• C. Allow diffusion of ions via gap junctions; link to microtubules.
• D. Anchor cells to the basement membrane via keratin filaments.

Answer: (C)

Desmosomes provide strong cell–cell adhesion in epithelial tissue, anchoring neighboring cells so the tissue can resist mechanical stress. They achieve this by linking cytoplasmic plaques to intermediate filaments, such as keratin, from one cell to those in the adjacent cell through desmosomal cadherins. This arrangement distributes pulling forces across cells and helps maintain tissue integrity.

The other options describe different junctions: tight junctions seal space between cells and associate with actin filaments; gap junctions form channels that allow ions and small molecules to pass between cells (not for mechanical connection); and hemidesmosomes attach cells to the basement membrane and connect to keratin filaments, but they mediate cell–matrix rather than cell–cell adhesion.