Intercalated discs transfer ions and molecules between cardiac muscle cells. Intercalated discs are a type of cell-to-cell junction found in the heart, and their main function is to transfer ions and molecules between cells and to provide mechanical support. This allows cardiac muscle cells to contract and relax together, creating a coordinated heartbeat. Intercalated disks allow the heart muscle to function as a synchronous unit, allowing the heart to contract and relax in a coordinated fashion.