Effects of electrical stimulation of ventricle at various time points during a Frog cardiac cycle:
1. at which time points of the cardiac cycle can an electrical stimulation induce extra systole?
2. explain how the extra systole can appear during this manipulation in terms of the refractory period of the ventricular action potential.
3. Stannius ligature experiment: what will happen to the beating rate of the two atria (right and left) versus the ventricle during the ligature?)
4. explain how these changes occur in the beating rate during the stannius ligature.
5. now the heart is completely devoid of neural or hormonal input. What will happen to the beating rate of all three chambers? What about the chamberĆ¢ĀĀs beating rate when they are surgically separated? explain possible mechanisms for the changes in the beating rate for each chamber.)
6. describe the effects of the following drugs on the heart rate and the force of ventricular contraction:
acetylcholine(1%), atropine (0.5%), Pilocarpine (2.5%), nicotine (0.2%), Epinephrine (0.1%), Isoproterenol (0.1%)
also, explain how each of the 6 chemicals above either mimic or inhibit the cardiac function