In my just recently published book, The Wine-Dark Sea Within: A Turbulent History of Blood, I dissect the advancement of the idea that a life-giving fluid courses within us, from the ancient Greeks to the Scientific Revolution to today.The Greeks observed the ebb and circulation of tides in the Aegean Sea (which Homer called the “wine-dark sea”) and inferred that a similar to-and-fro movement of blood ran within the human body. By determining the volume of blood in the left ventricle of the human heart (about 2 ounces) and then calculating the volume ejected per beat, per minute, and per hour, he approximated that an unreasonable 8,640 ounces or 540 pounds of blood would be produced in the liver and utilized up by the organs every hour if Galens model were proper. His hydraulic description of circular blood flow– out from the heart through the arteries and back to the heart through the veins– laid the foundation for our modern-day models of pathophysiological and physiological phenomena, including blood velocity, vascular resistance, blood pressure, and so on.
In my recently published book, The Wine-Dark Sea Within: A Turbulent History of Blood, I dissect the development of the concept that a life-giving fluid courses within us, from the ancient Greeks to the Scientific Revolution to today.The Greeks observed the ebb and flow of tides in the Aegean Sea (which Homer called the “wine-dark sea”) and presumed that a similar to-and-fro movement of blood ran within the human body. Through careful ligature experiments on fish, snakes, and other animals, Harvey revealed that these little doors opened and shut in such a method that blood could just stream one way through the veins, from the periphery towards the heart. By measuring the volume of blood in the left ventricle of the human heart (about 2 ounces) and then calculating the volume ejected per beat, per minute, and per hour, he approximated that an absurd 8,640 ounces or 540 pounds of blood would be made in the liver and utilized up by the organs every hour if Galens design were appropriate. His hydraulic description of circular blood flow– out from the heart through the arteries and back to the heart through the veins– laid the foundation for our modern-day models of physiological and pathophysiological phenomena, consisting of blood speed, vascular resistance, blood pressure, and so on. Routine interventions such as heart catheterizations and stent placements within arteries, as well as the flotation of pacemaker and defibrillator electrodes through veins, would be unimaginable without blood circulation, as they require the unidirectional flow of blood through arteries and veins as explained by Harvey.Extending the idea of an internal flow to outside the body as extracorporeal circulation is the basis for lifesaving assistance systems such as dialysis, the heart-lung machine for open heart surgeries, and heart help gadgets, such as the artificial heart.
