Galen had studied the human body as best he could by dissecting animals (Mantin and Pulley 60), and believed that the cardiovascular system was made up of two distinct plexi. According to him, blood was produced from the liver and carried to the various tissues throughout the body via arteries that also contained air absorbed from the lungs into the pulmonary veins. For centuries people believed Galen’s theories and thought that the cardiovascular system was an "open-ended" system in which blood and air simply dissipated at the ends of select veins and arteries, and this belief led to many medical errors, one major error being …show more content…
As the blood travels, the arteries branch out so that there are more and more of them, but they get smaller and smaller. Eventually, the blood reaches the capillaries…After passing through the capillaries, the blood returns to the heart by traveling through veins. Veins, which are small and numerous near the capillaries, form larger and larger vessels. At the same time, there are fewer and fewer of these larger vessels, so only a few large veins return blood directly to the heart.” (Shannon and Yunis 363)
Sadly, however, even after Harvey announced these discoveries and released recordings of his research and evidence of their legitimacy, people were doubtful and hesitant to accept it, and after he published his book on the circulation of blood he admitted that he lost a great amount of his patients because they thought he was crazy. (Dawson