Professor Saltzman describes the blood flow through the systemic and pulmonary circulatory system. More specifically, he describes, with the help of diagrams, the events that lead to blood flow in the body as a function of contraction/relaxation by specific chambers of the heart, and the effect of four valves which help direct flow. Important terms and concepts such as systole/diastole pressures, cardiac output (CO) as a function of heart rate (HR) and ejection volume (EV), and the action potential propagation that stimulates heart muscle contraction are discussed.