The Description of the Human Body He believed the heat of the heart somehow caused all movement of the body. Blood vessels he realized were pipes, he saw that veins carried digested food to the heart. (This was brought further by William Harvey. Harvey developed the idea of the circulation of the blood.) Descartes felt that an energetic part of blood went to the brain and there gave the brain a special type of air imbued with vital force that enabled the brain to experience, think and imagine. This special air then went through the nerves to the muscles enabling them to move. The Description of
Pulmonary circulation precise role of the lungs. The next addition to the human understanding of pulmonary circulation came with the Ancient Greeks. The physician Alcmaeon (520 - 450 BCE) proposed that the brain, not the heart, was the connection point for all of the vessels in the body. He believed that the function of these vessels was to bring the spirit (pneuma) and air to the brain. Empedocles (492 - 432 BCE), a philosopher, proposed a series of pipes impermeable to blood but continuous with blood vessels which carried the pneuma throughout the body. He proposed that this spirit was internalized with