ACTION POTENTIALS FROM DIFFERENT AREAS OF THE HEART Fast and Slow response ATRIUM Ⅴ ENTRICLE 0 90mv 90mv SA NODE 80mv 7 time
7 ACTION POTENTIALS FROM DIFFERENT AREAS OF THE HEART Fast and Slow Response mv 0 -90mv mv 0 -90mv mv 0 -80mv ATRIUM VENTRICLE SA NODE time
ELECTROPHYSIOLOGY OF THE FAST VENTRICULAR MUSCHE +20 AMP 2 0 3 Cardiac cell 90 0 300 t(msec)
8 ELECTROPHYSIOLOGY OF THE FAST VENTRICULAR MUSCLE t (msec) -90 0 +20 0 300 0 1 2 3 4 Cardiac Cell AMP
General description Phase 0: rapid Resting potential :-9omv depolarization mS Action potential Phase 1: early rapid +20 repolarization. 10 ms 2 Phase 2: plateau, slow 0 repolarization the 0 3 potential is around o 日 mV.100-150ms Phase 3, late rapid 0 repolarization. 100 50 ms 0 300 t(msec) Phase 4 resting potentials 9
9 t (msec) -90 0 +20 0 300 0 1 2 3 4 Phase 0: rapid depolarization, 1-2ms Phase 1: early rapid repoarization, 10 ms Phase 2: plateau, slow repolarization, the potential is around 0 mv. 100 – 150ms Phase 3, late rapid repolarization. 100 – 150 ms Phase 4 resting potentials General description Resting potential: -90mv Action Potential
lon Channels in Working Muscle Essentially same in atrial and ventricular muscle Best understood in ventricular cells 10
10 Ion Channels in Working Muscle ➢ Essentially same in atrial and ventricular muscle ➢ Best understood in ventricular cells
Ion Channels in Ventricula Cells Voltage-gated Nat channels Inward rectifier K+ channels L-type Ca2+ channels Several voltage-gated K+ channels
11 Ion Channels in Ventricular Cells ➢ Voltage-gated Na+ channels ➢ Inward rectifier K+ channels ➢ L-type Ca2+ channels ➢ Several Voltage-gated K+ channels