What are the 7 steps in excitation/contraction coupling?
1. AP spreads from cell membrane into the t-tubules 2. At plateau of AP, Ca conductance is increased and Ca enters the cell from the ECF 3. Entry of Ca triggers release of more Ca from the SR (Ca induced Ca release). 4 Intracellular Ca increases 5. Ca binds to troponin C, tropomyosin moves out of the way, removing inhibition of actin/myosin binding. 6 Actin and myosin bind, the thick and thin filaments slide past eachotehr and the myocardial cell contracts. The magnitude of tension that develops in proportional to the intercellular Ca. 7. relaxation occurs when Ca is re-accumulated by the SR by an active Ca ATPase pump