Describe the role of desmosomes in epithelial tissue.

• A. Provide strong cell–cell adhesion via intermediate filaments, resisting mechanical stress
• B. Form gap junctions for ion diffusion
• C. Secrete mucins
• D. Produce keratin

Answer: (A)

Desmosomes provide strong cell–cell adhesion by connecting the intermediate filament networks of neighboring epithelial cells. They use desmosomal cadherins (desmogleins and desmocollins) across the cell membranes, with dense cytoplasmic plaques containing proteins like desmoplakin and plakophilins that link to keratin filaments inside the cells. This setup distributes and resists mechanical forces, helping tissues withstand stretching and tearing. Desmosomes are essential in tissues under high mechanical stress, such as skin and heart. They’re not gap junctions (which allow ion diffusion), they don’t secrete mucins, and they don’t produce keratin themselves—desmosomes anchor the keratin networks to maintain tissue integrity.