The
discovery of the anatomy of the heart and circulatory system is a long series
of small steps spanning thousands of years. Many things which seem obvious to
us now where difficult discoveries for the early scientists. The following is
a rundown of the most influential discoverers of cardiovascular anatomy.
Galen
(130-200)
The great Greek-Roman physician and philosopher of Antiquity. He lived most of his life in Rome and was a personal physician of Roman Emperor Marcus Aurelius. His descriptions of human anatomy were mostly based on dissections of animals. His teachings were later canonized by the Church and strictly followed for almost 14 centuries. He had several important discoveries regarding heart anatomy, which included a description of valves, the differences between arteries and veins, and the postulate that arteries carry blood, not air (as it was previously thought). However, he did not understand the closed circulation of the blood and assumed that the liver, not the heart, was the center of the circulatory system.
The great Renaissance physician, founder of modern anatomy. Originally from Belgium, he went on to study medicine at the University of Paris, France. While being a student he noted marked differences between Galen's teaching and the real anatomy of dissected human bodies. He then went on, after five years of intensive investigation and thousands of dissections, to produce a magnificent De Humani Corporis Fabrica, the first human anatomy book (Vesalius was only 28 years old when the book was published in 1543). He traced the elaborate network of the blood vessels and in the first time in history described the heart accurately, noting that blood can not flow directly from the right to the left ventricle. The book contained seven volumes and over 300 illustrations (these engravings were made by the pupil of the renown artist Titian - Johann Kalkar, who made them under direct supervision of Vesalius). De Humani Corporis Fabrica produced a revolution in medicine and until now remains a valid and comprehensive coverage of the human body.
Spanish physician and theologian, who was burned at the stake for his religious beliefs, which were proclaimed heresy against Christianity. Besides his religious works he also contributed to the accurate description of the circulatory system. Servetus measured the amount of blood which went into the lungs and reasoned that this amount by far exceeds that which is required by the lung tissue itself, and therefore that the lungs must have some other purpose. He also traced the return of blood from the lungs to the heart through the pulmonary veins.
Italian physician, predecessor of William Harvey (see below). He described the four large blood vessels that come out of the heart and pointed out that the dilatation of the heart (diastole) collects blood, whereas the contraction (systole) pumps blood out. He was also the first man to mention that cardiac valves are one-way devices. His book, Da Re Anatomica, contains a description of blood flow forced into the proper direction by one-way valves and the powerful contractions of the heart muscle.
English physician, founder of modern physiology. He discovered the circulation of blood and the role of the heart in propelling it. Harvey was one of the most prominent doctors in England and physician to King James I and his son Charles I. He came to his conclusions not only by performing dissections but also by studying blood flow in live animals, and performing actual experiments (before, people believed that speculations alone are perfectly sufficient). Harvey's findings were published in 1628 in his book, Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus (Anatomical Essay on the Motion of the Heart and Blood in Animals). Harvey was incapable of observing capillaries but he proposed the existence of tiny vessels which connect the arterial and venous networks of the vessels.
Italian anatomist and physiologist. Before Malpighi people believed that blood
is converted to flesh at the ends of blood vessels. Using some of the first
microscopes Malpighi showed that small arteries are connected to the small venules
by even smaller blood vessels - capillaries. He was also the first to show that
the red color of blood is due to the presence of small corpuscles (red
blood cells). Malpighi described the microstructure of many other tissues,
thus becoming a father of histology.
