The first complete understanding of how arteries, veins, heart, and lungs function to form a single, complete circulatory system of human body is discovered by William Harvey in 1682 GC.
The human circulatory system represents the virtual definition of life. No system is more critical to our existence. Yet only 400 years ago, no one under stood our circulatory system. Many seriously thought that the thumping inside the chest was the voice of the con -science trying to be heard. Most thought that blood was created in the liver and consumed by the muscles. Some still thought that arteries were filled with air.
William Harvey discovered the actual function of the major elements of the circulatory system (heart, lungs, arteries, and veins) and created the first complete and accurate picture of human blood circulation. Harvey was also the first to use the scientific method for biological studies. Every scientist since has followed his example. Harvey’s 1628 book represents the beginning of modern physiology.