3期： 20 3期 慢Ca+通道失活 0 20 + 40 IK通道通透性个 -60 80 K+再生式外流 0 150 300 Time (ms) 快速复极化 至RP水平 (3期) 20 0 Ca+in (stow) 20 10 4期：因膜内Na]和[Ca2]升高 K+K 而膜外[K升高→激活离子泵 100 > 泵出Na+和Ca+,泵入K+→ 200 300 350 恢复正常离子分布 Na+ a
3期： 慢Ca2+通道失活 + IK 通道通透性↑ ↓ K+再生式外流 ↓ 快速复极化 至RP水平 （3期） 4期：因膜内[Na+]和[Ca2+] 升高， 而膜外[K+]升高→激活离子泵 →泵出Na+和Ca2+ ，泵入K+→ 恢复正常离子分布 3期 Na+ K+ Ca2+ K+ K+ ○泵 按任意键显示动画2 ○泵
Ionic Basis of AP ◆Phase O:Na+inward Phase 1:Na+channel closed,K* outward Phase 2:Ca2+inward=K+outward Phase 3:Ca2*channel closed,K+outward ◆Phase4:Na*-K*pump Ca2+pump
Phase 0：Na+ inward Phase 1：Na+ channel closed, K+ outward Phase 2：Ca2+ inward= K+ outward Phase 3：Ca2+channel closed, K+outward Phase 4 ：Na+-K+ pump Ca2+ pump Ionic Basis of AP
Electrical phenomena of autorhythmic cells Autorhythmic fast response cell-Purkinje cell 快反应自律细胞-浦肯野细胞 Autorhythmic slow response cell:S-A node and A-V node 慢反应自律细胞：窦房结细胞和房室结细胞
Electrical phenomena of autorhythmic cells Autorhythmic fast response cell –– Purkinje cell 快反应自律细胞－浦肯野细胞 Autorhythmic slow response cell： S-A node and A-V node 慢反应自律细胞：窦房结细胞和房室结细胞
AP of P cell in S-A node窦房结P细胞的动作电位 Maximal repolarization +20 Fast Ca2+ K channels channels potential -70mV (and Na* channels) 0 Threshold potential: -40mV Phase 0,3,4 Pacemaker potentials -60 (slow Ca2+channels) Time→
AP of P cell in S-A node 窦房结P细胞的动作电位 Maximal repolarization potential :-70mV Threshold potential: -40mV Phase 0,3,4
Phase Mechanism 20 0 零电位 -20 40 -60 阅电位 -80 1x失括 0 150 300 Time《ms) -65mV. When threshold is reached,fast calcium channels open and calcium rushes in. 100as 实房结细胞的动作电 Ca2 2+ a Na 0期：当4期自动去极化达到阈电位→激活慢钙通道 (Ica-L型)→Ca2+内流
Mechanism 0期：当4期自动去极化达到阈电位→激活慢钙通道 （Ica-L型）→Ca2+内流 Ca2+ Ca2+ Phase 0 阈电位 零电位 按任意键显示动画1、2