The “heart” of the functioning of the heart is the fast cell to cell communication between the cardiac myocytes. Upon generation of the pacemaker potential, the impulse is transmitted electrically to the adjacent cells. An action potential begins with rapid firing of fast Na+ channels resulting in rapid depolarisation (phase 0), following which there is an early repolarisation (phase 1). In the phase 2, Ca++ moves into the cells triggering massive release of calcium from the endoplasmic reticulum. And the cell contracts...
Delve into the depths of the molecular mechanism of the cardiac action potential. Click the