Medicine & USMLE

Gap Junctions

Cell Junctions
  1. Gap Junctions
  2. Tight Junctions
  3. Desmosomes


Gap Junctions, also called communicating junctions, are cytoskeleton components that form pores/channels and connect the cytoplasm of adjacent cells. This connection allows for the transport of water and ions between cells. Gap junctions are found in heart muscle cells and neurons. 

Key Points

  • Gap Junctions
    • Also called communicating junctions
    • Form pores/channels that connects the cytoplasm of adjacent cells
      • Connexons align to allow transport of water and ions between cells
    • Found in the heart (cardiomyocytes) and nerves (neurons)
      • These sites need rapid transfer of ions (charge) between cells
        • Intercalated discs of cardiomyocytes require rapid movement of ions to conduct action potentials between cardiomyocytes, enabling smooth progression of contraction
        • Neurons need rapid conduction of nervous impulses (action potentials)
          • Errors in gap junction genes can lead neurological diseases like multiple sclerosis and Huntington’s disease