Electrical Conduction and Contraction 1. An action potential is generated at the SA node 2. It spreads across the atrial surface and reaches the AV node 3. Atrial contraction begins during a 100ms delay at the AV node 4. The impulse then travels down the interventricular septum from the AV node by way of the AV bundle, heading toward the Perkinje fibers 5. The Perkinje fibers signal the papillary muscles to contract, and then distribute the impulse to the ventricular myocardium. Atrial contraction is now complete and ventricular contraction begins. 6. Ventricular contraction is completed. Total time = ~370ms
Amy Warenda Czura, Ph.D.
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SCCC BIO132 Chapter 20 Handout
Amy Warenda Czura, Ph.D.
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SCCC BIO132 Chapter 20 Handout
T-wave = ventricle repolarization ~160ms
QRS complex = atrial repolarization and ventricle depolarization ~80ms
P-wave = depolarization wave from SA node through atria ~80ms