The theories regarding blood circulation and blood pressure go far back into historical times. Since the time of the Greeks, blood was known to be the substance that sustained life.
Ancient civilizations also recognized the heart as the mechanics by which the blood was delivered to the tissues of the body.
The meaning of the Greek word arteria was ‘windpipe’. This is because in Greek physiology, the heart was the focus of respiration, as well as the center of the vascular system.
Way back in ancient Greece, Hippocrates and later Galen knew about arteries and veins.
Aristotle (384-322 BC) a biologist as well as a philosopher considered the heart as the center of system of blood vessels, but he made no distinction between arteries and veins, and showed no sign of any knowledge of the cardiac valves.
Galen was convinced veins and arteries were not connected and blood flowed both backward and forward form the heart. Galen believed that the liver made blood from food. The newly formed blood then proceed through vein to organs.
Galen’s characterization of the blood system carried authority for fifteen hundred years.
At the beginning of the third century BC Praxagoras insisted that the arteries contain no blood but only air.
Ancient history of blood circulation and blood pressure
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