-Gap junctions are a specialized intercellular connection between a multitude of animal cell-types. They allow the exchange of ions, second messengers, and small metabolites between adjacent cells and are formed by two unrelated protein families, the pannexins and connexins.
-Gap junctions are particularly important in cardiac muscle: the signal to contract is passed efficiently through gap junctions, allowing the heart muscle cells to contract in unison.
The tissue to have cells with the greatest number of gap junctions is the cardiac tissue.
Cardiac tissue refers to the involuntary, striated tissue present in the heart. It is made up of individual heart muscle cells called the cardiomyocytes. They are joined together by intercalated discs which contain the gap junctions. Gap junctions are the specialized intercellular connections which link the cytoplasm of two cells. Gap junctions play a crucial role in regulating the velocity and safe impulse propagation in the heart. They are abundantly found in the cardiac tissue helping in direct transmission of the deplolarizing current from cell to cell across the chambers of the heart. The signals for contraction of the cardiac muscle is passed through these gap junctions.
