Experiment 7:Analysis of frog s heart beat origin and observation of premature contraction and compensatory pause of myocardium 1.Teaching content Observate the normal Myocardial Contractive curve with different stimulus intensity and frequency,and induce premature systole and compensatory pause with electrostimulation,and then explore heart normal pacemaker with ligation. 2.Teaching objective (1)Understand the method and principle of analysis of frog s heart beat origin; (2)Be familiar with mechanisms,characteristics and significance of cardiac muscle effective refractory period; (3)Master recording method of frog s heart beat and observe effect of frequency of stimulation on myocardial excitability. Experiment 8:Discharge of depressor nerve in rabbit. 1.Teaching content Intubate one side of rabbit common carotid artery after anesthesia to record blood pressure,isolate one side of depressor nerve and place recording electrode on it,and then observe discharge of depressor nerve and effects of drugs. 2.Teaching objective (1)Understand characteristics of mammalian depressor nerve discharge; (2)Be familiar with relationship between depressor nerve discharge and arterial blood pressure; (3)Master the electrophysiological method of inducing depressor nerve discharge. Experiment 9:Record and analysis on human electrocardiogram (ECG) 1.Teaching content Place measuring electrode on the surface of precordial region,record the heart electric curve (ECG)and identify each wave,segment and interval of curve.Experiment 7：Analysis of frog`s heart beat origin and observation of premature contraction and compensatory pause of myocardium 1. Teaching content Observate the normal Myocardial Contractive curve with different stimulus intensity and frequency, and induce premature systole and compensatory pause with electrostimulation, and then explore heart normal pacemaker with ligation. 2. Teaching objective （1）Understand the method and principle of analysis of frog`s heart beat origin; （2）Be familiar with mechanisms, characteristics and significance of cardiac muscle effective refractory period; （3）Master recording method of frog`s heart beat and observe effect of frequency of stimulation on myocardial excitability. Experiment 8：Discharge of depressor nerve in rabbit. 1. Teaching content Intubate one side of rabbit common carotid artery after anesthesia to record blood pressure, isolate one side of depressor nerve and place recording electrode on it, and then observe discharge of depressor nerve and effects of drugs. 2. Teaching objective （1）Understand characteristics of mammalian depressor nerve discharge; （2）Be familiar with relationship between depressor nerve discharge and arterial blood pressure; （3）Master the electrophysiological method of inducing depressor nerve discharge. Experiment 9：Record and analysis on human electrocardiogram (ECG) 1. Teaching content Place measuring electrode on the surface of precordial region, record the heart electric curve （ECG） and identify each wave, segment and interval of curve