Krogh, << krawg, >> Schack August Steenberg (1874-1949), a Danish physiologist (scientist who studies how living things function), made important discoveries about the way that capillaries (small blood vessels) react when the body is doing muscular work. Krogh found that capillaries expand or contract in relation to the amount of blood that the body tissues require. An active muscle requires a larger number of open or enlarged capillaries than a less active muscle does. The additional open capillaries increase the surface area through which gases are exchanged. For his discoveries, Krogh was awarded the Nobel Prize in physiology or medicine in 1920.
Much of Krogh’s research work arose from his lasting interest in respiration, the exchange of oxygen and carbon dioxide between the body and its environment. His early work included research on the respiration of the frog. During this work, Krogh developed several new methods of physiological research. He also invented a number of new instruments. One invention of Krogh’s was the microtonometer, an instrument for measuring tiny air bubbles in the blood.
Krogh was born at Grena, in Denmark. He started studying physics and medicine at Copenhagen University in 1893 but later changed to zoology. He started research in physiology in 1897. Krogh served as professor of animal physiology at Copenhagen from 1916 to 1945.
