Explain how depolarization and repolarization of a cardiac m…

Explain how depolarization and repolarization of a cardiac myocyte leads to the cells contraction and then relaxation.  For full credit your explanation should include how each of the following play a role in the process: Action Potential Movement of Ca++  Sarcoplasmic reticulum T tubules Troponin/Tropomyosin Actin/Myosin Na+/Ca++ exchanger & Na+/K+ pump Contraction  Relaxation   For up to 5 points extra credit, also explain the movement of Na+ and K+ in the cardiac myocytes during the same time.