The Secrets of Circulation
Prairie Doc® Perspectives for week of May 31, 2020
By Richard P. Holm, MD
The medical history books reveal secrets of circulation and blood pressure that rival the best novels of intrigue. Years ago, before people had figured out how blood circulates, second century Greek scientist Galen, had the idea that blood moved from the right side of the heart to the left through unseen pores. That idea was not questioned for more than 1,000 years until a series of people in the mid-1500s finally broke with the old idea.
After great debate among leading thinkers of the time, English scientist and physician, William Harvey, and several anatomists and scientists finally convinced local medical leaders, and later those of the world, that blood pulses through the body on a great circular journey. It was fear of change that made the acceptance of this discovery so difficult.
Harvey, and other scientists, proved that venous blood is almost “sucked in” as it returns from the outer reaches of the body through gradually larger veins and eventually flows into the right ventricle of the heart. From the right ventricle (right lower part of the heart), blood is pumped into the lungs where hemoglobin gathers oxygen and releases carbon. From the lungs, oxygen rich blood flows to the left atrium (left upper part of the heart), to the left ventricle and is pumped out into arteries to feed almost all the cells of the body with oxygen.
From each tiny cell the blood picks up carbon waste, and the blood is drawn back to the right heart and lungs once again. Continuous circulation happens because the heart pump squeezes and relaxes, repeating the process some 80 times a minute from birth to death.
In my mind, the marvelous truth about the circle of blood flow is pure evidence of the beauty of both evolution and intelligent design. Circulation, like the rhythm of life, is a regular and recurring pulsing; a succession of surges over time like the flow of seawater and fish meeting the shore on an estuarial tide, the birth of lambs and calves, bursting forth on an early springtime prairie pasture or even the seventy to ninety-year life-cycle of humans, moving with joy, sorrow and grace from birth to natural death.
This essay, written by the late Richard P. Holm, MD, is an excerpt from his book “Life’s Final Season, A Guide for Aging and Dying with Grace” available on Amazon. Dr. Holm was founder of The Prairie Doc® and his legacy lives on through his Prairie Doc® organization. For free and easy access to the entire Prairie Doc® library, visit www.prairiedoc.org and follow Prairie Doc® on Facebook, featuring On Call with the Prairie Doc® a medical Q&A show streaming on Facebook and broadcast on SDPB most Thursdays at 7 p.m. Central.