In 1920, Danish physiologist August Krogh was awarded the Nobel Prize in Physiology or Medicine “for his discovery of the capillary motor regulating mechanism.”
What Happened
The principles of microcirculation and tissue oxygenation that Krogh helped establish are now relevant to understanding tissue injury, wound healing, exercise physiology and the effects of impaired blood flow. Because understanding how oxygen reaches tissues is central to conditions in which blood supply is impaired, including cardiovascular disease, peripheral vascular disease, diabetes and wounds that fail to heal, the work had important implications for medicine.
Background
Krogh combined experimental biology with quantitative measurements and developed instruments for studying physiological processes. His research included respiration, gas exchange and water and electrolyte regulation. Marie had diabetes and encouraged him to investigate the newly developed insulin treatment. The Krogh cylinder remains a useful conceptual model for studying oxygen diffusion, although modern research has refined the model using more detailed knowledge of blood flow, oxygen gradients and the three-dimensional structure of capillary networks. Krogh’s original explanation has evolved, but his decision to study circulation at the microscopic level changed the understanding of how blood supplies individual tissues. His work established the capillary network and oxygen diffusion as central to the study of tissue oxygenation and microcirculation.
Schack August Steenberg Krogh was born on November 15, 1874, in Grenaa, Denmark. He entered the University of Copenhagen in 1893, initially studying medicine before turning to zoology. In 1922, he and his wife, physician Marie Krogh, travelled to North America. Krogh retired from the University of Copenhagen in 1945 but continued his research. He died in Copenhagen on September 13, 1949, aged 74.
