Granit, Ragnar Arthur

born Oct. 30, 1900, Helsinki, Fin.
died March 12, 1991, Stockholm, Swed.

Finnish-born Swedish physiologist.

His "dominator-modulator" theory states that in addition to the retina's three kinds of cone cells, which respond to different colours, certain optic-nerve fibres (dominators) respond either to the whole spectrum or to specific colours (modulators). He also proved that light inhibits as well as stimulates optic-nerve impulses; other research helped determine the nerve pathways and processes by which receptors in muscles coordinate muscle action. He shared a 1967 Nobel Prize with George Wald and Haldan Keffer Hartline.

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▪ Swedish physiologist
born October 30, 1900, Helsinki, Finland
died March 12, 1991, Stockholm, Sweden

      Finnish-born Swedish physiologist who was a corecipient (with George Wald (Wald, George) and Haldan Hartline (Hartline, Haldan Keffer)) of the 1967 Nobel Prize for Physiology or Medicine for his analysis of the internal electrical changes that take place when the eye is exposed to light.

      Granit received an M.D. degree from the University of Helsinki in 1927, after which he conducted research at the University of Pennsylvania and at the laboratory of Sir Charles Scott Sherrington at Oxford, England. He was appointed professor of physiology at the University of Helsinki in 1937. A naturalized Swede, Granit joined the medical school of the Karolinska Institute, Stockholm, in 1940; he was named chairman of the institute's department of neurophysiology in 1946. A year earlier he had also become the director of the Nobel Institute for Neurophysiology in Stockholm. In the 20 years from 1956 to 1976 Granit also served as a visiting professor or researcher at numerous institutions.

      From studies of the action potentials in single fibres of the optic nerve, Granit formed his “dominator-modulator” theory of colour vision. In this theory he proposed that in addition to the three kinds of photosensitive cones—the colour receptors in the retina—which respond to different portions of the light spectrum, some optic nerve fibres (dominators) are sensitive to the whole spectrum while others (modulators) respond to a narrow band of light wavelengths and are thus colour-specific. Granit also proved that light could inhibit as well as stimulate impulses along the optic nerve. His book Sensory Mechanisms of the Retina (1947) is a classic work in the field of retinal electrophysiology.

      Granit then turned his attention to the study of the control of movement, specifically the role of muscle sense-organs called muscle spindles and tendon organs. He helped to determine the neural pathways and processes by which these internal receptors regulate and coordinate muscle action.

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Universalium. 2010.

Look at other dictionaries:

  • Granit , Ragnar Arthur — (1900–1991) Finnish neurophysiologist Born in the Finnish capital of Helsinki, Granit qualified as a physician from the university there in 1927. He taught at the university from 1927 until 1940, serving as professor of physiology from 1935. In… …   Scientists

  • Granit, Ragnar Arthur — (30 oct. 1900, Helsinki, Finlandia–12 mar. 1991, Estocolmo, Suecia). Fisiólogo sueco, nacido en Finlandia. Su teoría del dominador modulador establece que, además de los tres tipos de conos de la retina, que responden a diferentes colores,… …   Enciclopedia Universal

  • Ragnar Arthur Granit — (* 30. Oktober 1900 in Helsinki, Finnland; † 12. März 1991 in Stockholm, Schweden) war ein finnisch schwedischer Neurophysiologe und Nobelpreisträger. Granit lieferte wesentliche Arbeiten über die chemisch physiologischen Vorgänge in der Netzhaut …   Deutsch Wikipedia

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  • Arthur — /ahr theuhr/, n. 1. Chester Alan, 1830 86, 21st president of the U.S. 1881 85. 2. legendary king in ancient Britain: leader of the Knights of the Round Table. 3. a male given name. * * * (as used in expressions) Port Arthur Adamov Arthur Arthur s …   Universalium

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  • Ragnar Granit — Saltar a navegación, búsqueda Ragnar Arthur Granit (30 de octubre de 1900, Helsinki, Finlandia – 12 de marzo de 1991, Estocolmo, Suecia) fue un científico finés que ganó el Premio Nobel de Fisiología o Medicina en 1967 junto con Haldan Keffer… …   Wikipedia Español

  • Ragnar Granit — Ragnar Arthur Granit (* 30. Oktober 1900 in Helsinki, Finnland; † 12. März 1991 in Stockholm, Schweden) war ein finnisch schwedischer Neurophysiologe und Nobelpreisträger. Granit lieferte wesentliche Arbeiten über die chemisch physiologischen… …   Deutsch Wikipedia

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