The history of the capillary wall: doctors, discoveries, and debates.
In 1628, William Harvey provided definitive evidence that blood circulates. The notion that blood travels around the body in a circle raised the important question of how nutrients pass between blood and underlying tissue. Perhaps, Harvey posited, arterial blood pours into the flesh as into a sponge, only then to find its way into the veins. Far from solving this problem, Marcello Malpighi's discovery of the capillaries in 1661 only added to the dilemma: surely, some argued, these entities are little more than channels drilled into tissues around them. As we discuss in this review, it would take over 200 years to arrive at a consensus on the basic structure and function of the capillary wall. A consideration of the history of this period provides interesting insights into not only the central importance of the capillary as a focus of investigation, but also the enormous challenges associated with studying these elusive structures.
Hwa
Charlotte
C
Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA.
Aird
William C
WC
D000818:Animals; D002196:Capillaries / Q000502:physiology*; D002309:Cardiology / Q000266:history*; D002320:Cardiovascular Physiological Phenomena; D049670:History, 17th Century; D049671:History, 18th Century; D049672:History, 19th Century; D049673:History, 20th Century; D049674:History, 21st Century; D006801:Humans; D008955:Models, Cardiovascular; D010820:Physicians / Q000266:history*; D010827:Physiology / Q000266:history*