1. Explain how regular exercise reduces the risk of heart disease.

2. Define stroke volume and discuss how stroke volume can be altered. Explain the effect of changes in stroke volume on cardiac output using the appropriate formula for determining cardiac output.

3. Trace the path of one drop of blood from the time it enters the right atrium until it enters the left atrium. What is this circuit called?

4. The refractory period of cardiac muscle is much longer than that of skeletal muscle. Why is this a desirable functional property?