While blood has been observed and dealt with since the dawn of humanity, William Harvey is widely credited with first studying and accurately describing the circulation of blood in the 17th century.
Here's a more detailed breakdown:
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Early Observations: Blood's importance to life was recognized long before any scientific understanding. Ancient civilizations, including the Egyptians and Greeks, had theories about blood's role in the body. However, these were often based on philosophical concepts rather than empirical observation.
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Ibn al-Nafis: It's crucial to acknowledge that the concept of pulmonary circulation was described by the Syrian physician Ibn al-Nafis in the 13th century. He accurately described the movement of blood from the right ventricle of the heart to the lungs, where it's oxygenated, and then to the left ventricle. Unfortunately, his work remained largely unknown in the Western world for centuries.
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William Harvey and the Circulation of Blood: William Harvey (1578–1657) is most often credited because he conducted experiments and published his findings in De Motu Cordis ("On the Motion of the Heart and Blood") in 1628. He demonstrated through quantitative reasoning and vivisection that blood circulates continuously within a closed system, driven by the heart. He accurately described the roles of the heart, arteries, and veins in this process.
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Harvey's Key Contributions:
- Experimental Evidence: Harvey used experiments to prove that blood circulated.
- Quantitative Analysis: He calculated the amount of blood pumped by the heart and demonstrated that the liver could not possibly produce that much blood, thus supporting the theory of circulation.
- Detailed Description: He provided a clear description of the circulatory system, including the role of valves in veins.
Therefore, while Ibn al-Nafis anticipated aspects of pulmonary circulation centuries earlier, William Harvey's comprehensive experiments and widespread publication made his model of complete blood circulation the accepted understanding in the Western world. His work is considered a cornerstone of modern physiology.
