August Krogh

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August Krogh

August Krogh ( Schack August Steenberg Krogh; born November 15, 1874 in Grenaa ( Djursland ), † September 13, 1949 in Copenhagen ) was a Danish physiologist and zoologist . For his discovery of the capillary motor regulation mechanism , he received the Nobel Prize in Medicine in 1920 .

life and work

Early years and education

August Krogh's parents were Viggo Krogh, a shipbuilder, and Marie Krogh, nee Drechmann. He was already very interested in the natural sciences during his school days and carried out simple experiments with animals and plants. He was strongly influenced by his teacher William Sörensen, who showed him experiments in physiology . In 1893 he began studying medicine at the University of Copenhagen , but quickly switched to zoology , which was more suited to him.

Around 1896, as a student, he worked on the hydrostatic mechanism of the Corethra larvae, a genus of tufted mosquitoes whose larvae live in the water and rise and fall through changes in their density. He found that these larvae have gas bubbles in their bodies that could be filled with oxygen from the surrounding water if necessary. His results were not published until 1911.

In 1897 he got a job in Christian Bohr's laboratory , where he dealt with medical physiology and, after graduating, became Bohr's assistant at the Institute for Medical Physiology in Copenhagen. He studied the gas exchange of living organisms and was honored with the Seegen Prize , an award from the Austrian Academy of Sciences , for the publication of an article on the release of gaseous nitrogen by the body .

In 1902 he interrupted his studies for a research trip to Greenland , where he dealt with physico- limnic issues. He studied the tension in carbon dioxide and the oxygen content in the water of springs , streams and the sea . The role of the sea in the oxygen balance of the atmosphere was an important research area, on which he published several important publications.

His doctorate took place in 1903 on the basis of an investigation into gas exchange in frogs . Here he was able to prove that the animals' skin respiration was largely constant, while the proportion of the gas that is absorbed through the lungs fluctuated very strongly and is controlled by the vagus nerve . After completing his doctorate, he studied the Inuit diet in Greenland and the effects of their very one-sided, meat-based diet on their bodies. In 1905 he married the medical student Birte Marie Jörgensen, who also received her doctorate in 1914. Her dissertation also dealt with gas exchange, albeit in humans. He and her had four children, three of whom were daughters. Marie died in 1943.

Research on gas exchange in the lungs

In 1908 August Krogh got a specially created assistant professorship for animal physiology at the University of Copenhagen, which was converted into a full professorship in 1916. Krogh held this chair until his retirement in 1945. He then worked in his private laboratory in Gjenstofte , which was made available to him by the Scandinavian Insulin Foundation .

Right at the beginning of his professorship, Krogh rejected his first hypothesis that gas exchange in the lungs was an active additional form of gas uptake. Instead, he and his wife put forward a completely new theory of gas uptake and were able to confirm it. With the help of the microtonometer he developed , he was able to prove in 1910 that the oxygen pressure in the alveoli , the alveoli , is always higher than in the surrounding blood vessels, so that the gas exchange between the lungs and blood is exclusively due to a diffusion process. In doing so, he contradicted the theories favored at the time by John Burdon Sanderson Haldane and his former laboratory manager Christian Bohr . The work of other researchers confirmed Krogh's findings.

Further work by Krogh dealt with the binding and transport of oxygen in the blood as well as the gas exchange between the blood and the surrounding tissue. Together with Christian Bohr and Karl Albert Hasselbalch , he was able to demonstrate the influence of carbon dioxide pressure on the capacity of hemoglobin to absorb oxygen in the blood.

The capillary motor regulation mechanism

Together with Johannes Lindhard , August Krogh researched another general issue of blood flow in order to find an explanation for the massive increase in the need for muscle work . In order to achieve this, the blood flow, especially of the venous blood, had to be highly variable and, during rest phases, it could not be sufficient to completely fill the heart ventricle . This could be shown by the experiments, which confirmed these theories.

Another important result was a more detailed analysis of the increase in blood and oxygen throughput in the muscles during exercise. Since the oxygen pressure in a resting muscle was always very low, the sufficient increase in the oxygen supply could only be explained by an increase in the area where oxygen exchange is possible. The following research by Krogh built on this basic consideration, which led to an understanding of the involvement of the blood capillaries in the muscles and for which he was awarded the Nobel Prize in 1920. Here he was able to show that the capillary network of the muscles only fills with blood when the muscle is active. He researched this process known as the “ capillary motor regulation mechanism ” and was able to explain both the activation of the capillary blood flow and the regulation.

After the Nobel Prize, he continued his research in this area and published it in his book The Anatomy and Physiology of the Capillaries and other publications in 1922 . In doing so, he expanded his work to other areas of the complex, such as heat regulation , the influence of nutrition and the capacity of muscle performance, the formation of lactic acid in muscles, training and muscle fatigue as well as the connection with kidney activity . The Institute for Sports Science at the University of Copenhagen has been renamed the August Krogh Institute.

More work

In addition to the work on gas exchange detailed above, August Krogh occupied himself with many other questions of physiology. He demonstrated a great influence of the outside temperature in both insects and vertebrates, which he explained using the Arrhenius equation . He was also able to prove external influences on the development of the animals. Krogh also expanded his work on gas exchange to include tracheal breathing in insects. He proved that here, too, the absorption of oxygen takes place exclusively through diffusion. For the release of carbon dioxide, he hypothesized that it is released via the body surface and does not get into the trachea, since the concentration of carbon dioxide measured here is only very low. For the increased oxygen consumption during flight by the flight muscles , Krogh was able to demonstrate a ventilation mechanism through a slight contraction of the trachea.

For the breakdown of body fat for muscle work, Krogh demonstrated a loss of 11% compared to the carbohydrates , which he explained with the conversion of fat to carbohydrates. Another focus of his work group was the research of water uptake and the exchange of ions in living cells.

With his pupil Torkel Weis-Fogh he worked on insect flight.

Honors

In addition to the Nobel Prize for Medicine and Physiology, August Krogh received a number of other awards for his work. He was awarded honorary doctorates from the universities of Edinburgh , Budapest , Lund , Harvard , Göttingen , Oslo and Oxford . In 1916 he became a member of the Academy of Sciences in Denmark, 1931 the American Academy of Arts and Sciences , 1937 the Royal Society in London , 1941 the American Philosophical Society , the National Academy of Sciences and the German Academy of Natural Scientists Leopoldina . In the same year he received the Baly Medal from the Royal College of Physicians in London. He was also a member of the Royal Physiographical Society in Lund , the Royal Swedish Academy of Sciences and the Royal Society of Edinburgh . The UK Antarctic Place-Names Committee named Krogh Island in Antarctica after him on September 23, 1960 .

Fonts

  • The respiratory exchange of animals and man. Longmans, Green & Co., London a. a. 1916 ( Textarchiv - Internet Archive ).
  • The anatomy and physiology of capillaries (= Mrs. Hepsa Ely Silliman memorial lectures. 18, ZDB -ID 986216-X ). Yale University Press et al. et al., New Haven CT et al. a. 1922 ( Textarchiv - Internet Archive ).
    • Anatomy and physiology of the capillaries (= monographs from the entire field of the physiology of plants and animals. 5, ZDB -ID 500760-4 ). In German translation by U. Ebbecke. Springer, Berlin a. a. 1924 ( Textarchiv - Internet Archive ).
  • Osmotic regulation in aquatic animals. Cambridge University Press, Cambridge u. a. 1939.
  • The comparative physiology of respiratory mechanisms (= The William J. Cooper Foundation lectures. 1939, ZDB -ID 2285483-6 ). University of Pennsylvania Press, Philadelphia PA 1941.

literature

Web links

Commons : August Krogh  - collection of images, videos and audio files

Individual evidence

  1. ^ Les Prix Nobel Submissions  - Internet Archive
  2. ↑ Arnd Krüger : History of movement therapy. In: Malte Bühring , Fritz H. Kemper (Hrsg.): Naturopathic methods and unconventional medical directions. Loose-leaf collection. 8. Subsequent delivery. Springer, Berlin a. a. 1999, 07.06, pp. 1-22.
  3. ↑ Gisela Sjøgaard: The August Krogh Institute: Capillaries and beyond. In: Scandinavian Journal of Medicine & Science in Sports. Volume 25, Supplement 4, 2015, ISSN  0905-7188 , pp. 16-21, doi: 10.1111 / sms.12552 .
  4. ↑ Member entry of August Krogh at the German Academy of Natural Scientists Leopoldina , accessed on October 12, 2012.
  5. ↑ August Krogh . In: Theodor Westrin, Ruben Gustafsson Berg, Eugen Fahlstedt (eds.): Nordisk familjebok konversationslexikon och realencyklopedi . 2nd Edition. tape 36 : Supplement: Globe – Kövess . Nordisk familjeboks förlag, Stockholm 1924, Sp. 1229 (Swedish, runeberg.org ).
  6. ^ Fellows Directory. Biographical Index: Former RSE Fellows 1783–2002. (PDF file) Royal Society of Edinburgh, accessed December 28, 2019 .
personal data
SURNAME Krogh, August
ALTERNATIVE NAMES Krogh, Schack August Steenberg (full name)
BRIEF DESCRIPTION Danish doctor and zoologist, Nobel laureate in medicine
DATE OF BIRTH November 15, 1874
PLACE OF BIRTH Grenaa
DATE OF DEATH September 13, 1949
Place of death Copenhagen