Who first studied about the circulatory system in man?

The study of the human circulatory system has a long history, with contributions from numerous scholars and physicians throughout the centuries. However, the first person specifically credited with studying the circulatory system in man is considered to be the ancient Greek physician Galen of Pergamon. Galen lived from approximately 129-201 AD and was one of the most prominent medical authorities of his time.

Galen's theories and observations were influential in medicine for over 1,500 years. He conducted numerous experiments, such as dissections of animals, and demonstrated that blood flows through vessels in the body. He also believed that blood ebbed and flowed like tides and was consumed and replaced continuously. While some aspects of his understanding were later proved to be incorrect, his contributions to the field of anatomy and physiology were significant and laid the groundwork for future advancements.

In the 16th century, the Flemish anatomist Andreas Vesalius (1514-1564) made important corrections and additions to Galen's work on the circulatory system. Through careful observation and dissection of human cadavers, Vesalius provided more accurate descriptions of the structure of the heart, blood vessels, and valves.

The breakthrough understanding of the circulatory system as we know it today came in the 17th century with the work of William Harvey (1578-1657). Harvey's systematic experiments and observations challenged Galen's theories and established the concept of blood circulation. His most notable contribution was demonstrating that blood moves in a continuous circuit, being pumped by the heart through arteries and returning via veins. Harvey's comprehensive book "De Motu Cordis" (On the Motion of the Heart and Blood) published in 1628, presented his findings and revolutionized the understanding of the circulatory system.

Therefore, while there have been many contributors to the study of the circulatory system, Galen of Pergamon is considered the first individual to specifically focus on and make significant observations about the circulatory system in humans. His contributions, along with those of Vesalius and Harvey, played crucial roles in shaping our current knowledge and understanding of this essential physiological system.