山东大学：《医学生理学 Medical Physiology》课程教学资源（PPT课件讲稿，人体生理学 Human Physiology）Chapter 4 Cardiovascular Physiology section 2 Electrical Properties of the Cardiac Cell

Section Electrophysiology of the heart

2 Section 2 Electrophysiology of the Heart

CARDIAC ELECTROPHYSIOLOGY R ST P-R- QRS Q-T-

3 CARDIAC ELECTROPHYSIOLOGY

Two kinds of cardiac cells The conduction system of the heart Interatrial septum Right and left bundle branches 1. The working cells Sinoatrial node (SA node) Atrioventricular pecial property node(Av node) contractility Atrioventricular bundle of His Purkinje fibers Interventricular septum Apex of heart

4 1, The working cells. Special property: contractility Two kinds of cardiac cells

2, Special conduction system including h The conduction system of the heart Sinoatrial nodes Interatrial septum Atrioventricular Right and left bundle branches node Sinoatrial node. (SA node) Atrioventricular Atrioventricular node(Av node) TU N bundle(bundle of Atrioventricular bundle His) (bundle of His and Purkinje Nancy Marshburn system Purkinje fib Interventricular septum Apex of heart Special property automaticity

5 including the Sinoatrial node, Atrioventricular node, Atrioventricular bundle (bundle of His), and Purkinje system. Special property: automaticity 2, Special conduction system

I. Transmembrane Potentials of Myocardial eels

6 I. Transmembrane Potentials of Myocardial Cells

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