Which statement describes the location of gap junctions on epithelial cells?

• A. They are found basally
• B. They are found laterally
• C. They are found apically
• D. They are found throughout all surfaces

Answer: (B)

Gap junctions enable direct cytoplasmic exchange of ions and small molecules between neighboring epithelial cells, coordinating activity across the cell layer. In epithelia, cells contact each other mainly along their lateral surfaces, so the junctions that allow this intercellular communication are located on the lateral membranes. They are not on the apical surface, which faces the lumen, nor on the basal surface, which contacts the basement membrane. Therefore, the best description is that gap junctions are found laterally.