Until around 1628, the beliefs of Galen, a Greek physician from the second century AD., were still followed in relation to the heart and circulatory system. He believed there were two types of blood, nutritive blood and vital blood, one made from the liver, and one made by the heart. He believed the heart sucked blood from the veins, and flowed through the septum of the heart from ventricle to ventricle. William Harvey, however, questioned these beliefs, rebellious for his time, and went on to further investigate the circulatory system. After dissections of animals and animal hearts, he observed that the heart valves only allow blood to flow in one direction, as well as ventricles contracted together with each heartbeat. Harvey removed a beating heart from a living animal, and the heart continued to beat, meaning that is was acting like a pump, rather than sucking as Galen had believed. Harvey discovered that blood must be flowing on a “closed circuit,” rather than being consumed. Harvey continued to ask questions and continued to find answers, and his published work raised even more questions for physicians and scientists alike. Harvey’s work was the foundation for modern research of the heart and cardiovascular medicine, and may be considered to be one of the most important contributions in the history of medicine.
For more information on William Harvey and the circulatory system, visit
http://www.accessexcellence.org/AE/AEC/CC/heart_background.phpand
http://physiologyonline.physiology.org/cgi/content/full/17/5/175Phillips, Jr., Roger E. "The Heart and the Circulatory System."
Access Excellence. The National
Health Museum, Web. 25 Oct 2009.
/CC/heart_background.php>.
Schultz, Stanley G. "William Harvey and the Circulation of the Blood: The Birth of a Scientific
Revolution and Modern Physiology ."
Physiology. Web. 25 Oct 2009.
.
Interesting how the human body is conceived of using mechanical explanations at this time. It fits well with the emerging mechanical philosophy in general, and the whole clockmakers paradigm. I suppose there is no real conflict with religion in this sense either, as God is the ultimate clockmaker, or body maker, as the case may be.
ReplyDeleteI wonder what types of medical practices of the time involved blood and how Harvey's explanation impacted medical practice in general.
One more thought--we have been working hard on Halloween plans and decorations today, and as we create our haunted basement, I was thinking about Poe's The Tell Tale Heart. What a great example of something from the horror genre that relies directly on Harvey's findings!
ReplyDeleteFirst off, great presentation. Second, I find it interesting that until William Harvey, people believed that the blood to the heart came from many directions. I also found it interesting that he took a heart out of an animal to see first hand what the heart does in action, rather than just guessing.
ReplyDeleteI learned about Galen in my project research as well. I was looking for where people of the time believed mental activity originates from...many believed it was either from the heart, or the brain.
ReplyDeleteYour presentation on this topic was both hilarious and informative, great job. It's funny how even though Galen's thoughts were way off (there is not a type of blood made in the liver) that they still have a little relation to how we know the heart works today. We now know (well I guess they thought they knew as well) that there ARE two types of blood flowing through the body, oxygenated blood and deoxygenated blood, which has a little simalarity to the original thought that there is two different types of blood.
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