Fibroblasts are smaller but more numerous than cardiomyocytes, and several fibroblasts can be attached to a cardiomyocyte at once. When attached to a cardiomyocyte they can influence the electrical currents passing across the muscle cell's surface membrane, and in the context are referred to as being electrically coupled.[14] Other potential roles for fibroblasts include electrical insulation of the cardiac conduction system, and the ability to transform into other cell types including cardiomyocytes and adipocytes.[2]