Circulation
In this topic you will learn about the structure of the human circulatory system as well as blood, heart disease and the effect of exercise on our circulatory system.
Structure of Arteries, Veins and Capillaries
The average adult heart beats 72 times a minute; 100,000 times a day; 3,600,000
times a year; and 2.5 billion times during a 70-year span.