Summary

Galenic Sources in Anatomy and Physiology

After the renewed legality of human dissection as a part of science and philosophy, there was a sudden development of interest in the fields of anatomy and physiology. Up to this point in time, the Galenic view of the human body was taught in universities by a professor who narated and supplied the thought and reasoning while a dissectionist supplied the model. According to the Galenic corpus, there is, in the body, a continuous ebb and flow of blood to the liver. From the liver it continues to the ventricles where it is combined with air through the pulmonary veins and is endowed with "vital spirit". Galen also classified 3 different systems of the body saying they were all disconnected: the veinous system, the arterial system, and the nervous system.

Renaissance Anatomists

Andreus Vesalius

     Andreus Vesalius was born in 1514 in Flanders, Belgium. He studied medicine in Paris later becoming a dissectionist and the Demonstrator of Anatomy at Padua, Italy.  Wanted to reconstruct the Galenic physiology on the human body.  Vesalius also moved to remove the barrier between the lecturer and the barber-dissectionist. He advocated a more craftlike approach to medicine and successfully blended the role of the dissectionist with the anatomist. In 1543 Visalius published his work The Fabric of the Human Body. In this masterpiece of both science and art, Vesalius sought to make a full study of anatomony on the Galenic model.  Following the structure of Galen's On Anatomical Procedures, he addressed about 300 errors he found in Galen due to his predecessor's inability to utilize human dissection. 

Michael Servetus

Michael Servetus developed a theory of circulation that brought about the knowledge of the lesser circulation of the blood.  This idea included the theory that blood is pumped from the heart to the lungs nad then back to the heart from the lungs.  Servetus' ideas did not reach popularity though as some of his other heretical ideas caused him and all his works to be burned at the stake. 

Realdo Columbo

Realdo Columbo reached the same conclusions about the lesser circulation of the blood, but it was his work that was widely known and distributed. 

Heronimus Fabricius

A professor at Padua, a university noted for its study of anatomy, Heronimus Fabricius is known for his study on the structure of veins. He discovered that there were valves in the veins of the cirulatory system.  He hypothosized that these valves restricted the flow of veinous blood so there would not be too much blood in one area, such as the feet when a person stands up.

William Harvey

     William Harvey (1578-1657) was a physician to King Charles I, and was from an upper middle class family. As he was given access to the royal hunting grounds, he regularly practiced dissection on practically any animal or cadaver he could find. Harvey made three arguments that provided evidence for the circulation of blood throughout the body, not only limited to the three systems as previously believed. First, there was a quantitative argument. Harvey estimated that approximately 2 oz of blood could be stored in a ventricle at a time. Assuming that only 1 or two drams (1 dram=1/8 oz) with every pump of 2 oz of blood out of the heart was lost during transit (for nourishment, etc.), within a day the heart would have produced more blood that was possible of being held in the human body. Furthermore, the body would have no way of producing that much blood based on the human diet. This led Harvey to argue that blood was not simply made and used, but cycled around the body. His second argument was an anatomical argument. This involved pinching blood vessels and cutting them in order to see in which direction blood flowed. In an artery, for example, if one cuts on the side closest to the heart, blood will spurt out, but if one cuts on the other side it just oozes out. The reverse is true for veins, though the spurting is not as intense. Harvey's final argument was an observational argument involving ligation.

 William Harvey observed the circulation of the body and through his observations, he theorized a new circulatory system that involves recycled blood and one long chain of circulation between the arteries and the veins. 

Primary Sources

Key Terms and Definitions

De Humani Corporius Fabrici - the master work of Vesalius that completely rethought and anazlyzed the Galenic view of anatomy. Considered a masterpiece of science for its information and a masterpiece of art for its numerous diagrams of the human body with Greek influences.

Systole - Contraction of the heart

Diastole - Expansion of the heart

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