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Gap junction

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noun, plural: gap junctions

A type of cell junction characterized by the intercellular channel that is formed in between neighboring cells, and allows direct communication between cells, i.e. allowing small molecules, ions, and electrical impulses to move between cells without passing the outside of cells


Cell junctions are specialised junctions between cells. They occur within animal tissues (e.g. animal tissues, nerve tissues, etc.). They are formed by multiprotein complexes that provide contact between adjacent cells or between a cell and the extracellular matrix. There are three major types of cell junctions: (1) tight junctions, (2) gap junctions, and (3) anchoring junctions (e.g. desmosomes).

A gap junction is a type of cell junction characterized by an intercellular bridge (i.e. ~2 nm gap) that forms between the membranes of neighboring cells. It is involved in intercellular communication, i.e. allowing the direct passage of ions, small molecules, or electrical impulses from one cell to another. Thus, these molecules would not pass the outside of cells but move directly from one cytoplasm to the next. Gap junctions that are found in nerves are referred to as an electrical synapse whereas gap junctions in smooth muscles are called nexuses. In cardiac muscle tissues, gap junctions form a part of the intercalated disc. Although gap junctions are present in many types of animal tissues, they are not found in adult skeletal muscle, sperms, and erythrocytes. Gap junctions are also not found in certain animals, such as sponges and slime molds.

Abbreviation / Acronym: GJ


  • nexus
  • macula communicans
  • communicating junction

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