What is the primary function of a desmosome?

The primary function of a desmosome is indeed to join intermediate filaments between neighboring cells. Desmosomes are specialized cell junctions that play a critical role in providing structural stability to tissues by anchoring the cytoplasmic intermediate filaments of adjacent cells together. This connection helps distribute mechanical stress across a tissue, allowing it to withstand tensile forces.

Desmosomes are particularly abundant in tissues that experience significant mechanical stress, such as cardiac muscle and epithelial tissues. The linking of intermediate filaments through desmosomes creates a robust network that maintains the integrity of the cell sheet and contributes to the overall resilience of the tissue.

In contrast, the other options describe functions of different cellular structures. For example, anchoring intermediate filaments to the basal lamina is characteristic of hemidesmosomes, not desmosomes. The passage of small ions and molecules through cell membranes is generally facilitated by gap junctions, while sealing neighboring cells together to prevent leakage is primarily the function of tight junctions. These distinctions clarify the specific role of desmosomes in cellular architecture and tissue integrity.