<P> A succession of researchers proceeded to refine the body of anatomical knowledge, giving their names to a number of anatomical structures along the way . The 16th and 17th centuries also witnessed significant advances in the understanding of the circulatory system, as the purpose of valves in veins was identified, the left - to - right ventricle flow of blood through the circulatory system was described, and the hepatic veins were identified as a separate portion of the circulatory system . The lymphatic system was also identified as a separate system at this time . </P> <P> The study of anatomy flourished in the 17th and 18th centuries . At the beginning of the 17th century, the use of dissecting human cadavers influenced anatomy, leading to a spike in the study of anatomy . The advent of the printing press facilitated the exchange of ideas . Because the study of anatomy concerned observation and drawings, the popularity of the anatomist was equal to the quality of his drawing talents, and one need not be an expert in Latin to take part . Many famous artists studied anatomy, attended dissections, and published drawings for money, from Michelangelo to Rembrandt . For the first time, prominent universities could teach something about anatomy through drawings, rather than relying on knowledge of Latin . Contrary to popular belief, the Church neither objected to nor obstructed anatomical research . </P> <P> Only certified anatomists were allowed to perform dissections, and sometimes then only yearly . These dissections were sponsored by the city councilors and often charged an admission fee, rather like a circus act for scholars . Many European cities, such as Amsterdam, London, Copenhagen, Padua, and Paris, all had Royal anatomists (or some such office) tied to local government . Indeed, Nicolaes Tulp was Mayor of Amsterdam for three terms . Though it was a risky business to perform dissections, and unpredictable depending on the availability of fresh bodies, attending dissections was legal . </P> <P> The supply of printed anatomy books from Italy and France led to an increased demand for human cadavers for dissections . Since few bodies were voluntarily donated for dissection, royal charters were established which allowed prominent universities to use the bodies of hung criminals for dissections . However, there was still a shortage of bodies that could not accommodate for the high demand of bodies . Until the middle of the 18th century, there was a quota of ten cadavers for each the Royal College of Physicians and the Company of Barber Surgeons, the only two groups permitted to perform dissections . During the first half of the 18th century, William Cheselden challenged the Company of Barber Surgeon's exclusive rights on dissections . He was the first to hold regular anatomy lectures and demonstrations . He also wrote The Anatomy of the Humane Body, a student handbook of anatomy . In 1752, the rapid growth of medical schools in England and the pressing demand for cadavers led to the passage of the Murder Act . This allowed medical schools in England to legally dissect bodies of executed murderers for anatomical education and research and also aimed to prevent murder . To further increase the supply of cadavers, the government increased the number of crimes in which hanging was a punishment . Although the number of cadavers increased, it was still not enough to meet the demand of anatomical and medical training . </P>

Timeline of the historical development of anatomy and physiology