Cardiac Electrophysiology Tutorial

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1. What are the normal concentrations of sodium, potassium, and calcium ions inside and outside of a cardiac myocyte?
2. What is the Nernst potential?  What is an equilibrium potential?
3. How does changing the concentrations of sodium, potassium, and calcium ions inside and outside the cell affect the resting membrane potential in cardiac cells?
4. What is the role of the sarcolemmal Na⁺/K⁺-ATPase in the generation and maintenance of cardiac membrane potentials?
5. How are calcium gradients maintained across the cardiac cell membrane?
6. How do changes in the relative ionic conductances of sodium, potassium, and calcium ions affect the membrane potential?
7. How are cardiac action potentials different from those found in nerve cells?
8. What ionic currents are responsible for pacemaker action potentials?
9. How do autonomic nerves, circulating catecholamines, extracellular potassium concentrations, thyroid hormone, and hypoxia alter pacemaker activity?
10. What ionic currents are responsible for non-pacemaker action potentials?
11. What is the effective refractory period (ERP) for an action potential and what can cause it to lengthen or shorten?
12. What is the normal sequence and pathways for depolarization within the heart?
13. How do autonomic nerves, circulating catecholamines, cellular hypoxia, and drugs blocking sodium channels  alter conduction velocity within the heart?

Revised 11/03/06