Which of the following cell-cell junctions would help skin cells withstand mechanical stress by directly anchoring the intermediate filaments of adjacent cells?DesmosomesGap junctionsTight junctions

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11ecba2d_0fd6_e9a5_a3bf_11c58f568daf_MD0008_00 Cell-cell junctions, such as desmosomes, gap junctions, and tight junctions, are structures that attach adjacent cells to one another. Cell junctions are prominent in epithelial tissue, which is composed of densely packed cells and very little extracellular matrix. Desmosomes provide tensile strength to epithelial cell sheets by anchoring the cytoskeletons, specifically the intermediate filaments, of two cells together. This creates a continuous cytoskeletal network that spans the entire epithelial sheet, one through which mechanical stress (eg, pulling, stretching, tension) can be distributed. Desmosomes are found predominantly in tissues that are subject to high levels of mechanical stress (eg, muscle tissue, epithelial layers of the skin) and prevent tissue tearing (Number I). (Number II) Gap junctions are cell-cell junctions that mediate communication between cells. Protein channels (connexons) in one cell align with complementary channels in another cell to form pores that facilitate the passive and bidirectional exchange of ions and small solutes. Gap junctions are found in cell populations that depend on coordinated activity, such as smooth muscle, cardiac muscle, or neural tissue. (Number III) Tight junctions are cell-cell junctions that prevent water and solutes from diffusing between cells and across the epithelial cell layer. These junctions form a watertight seal that fully encircles the apical end of every cell in the basal epithelial sheet. Tight junctions serve as a barrier and separate tissue space; they are found in a number of tissues, including skin, gastrointestinal tract, and testis. Educational objective: Desmosomes, gap junctions, and tight junctions are cell-cell junctions that provide tissue with mechanical strength, cytoplasmic continuity, and watertight seals, respectively.

Which of the Following Cell-Cell Junctions Would Help Skin Cells