title: [Blood perfusion of the liver under physiological and pathological conditions - mechanisms and clinical importance (author's transl)].
abstract: It has been shown, that measurement of total hepatic blood flow is not of great diagnostic value: normal functioning of this organ is dependant on blood flow only to a minor degree and diseases of the liver usually go along with only minor changes of total blood flow. There are two reasons for this phenomenon: 1) liver cells are able to extract oxygen from blood exhaustively 2) regulation of hepatic arterial blood flow is almost autonomous and compensates well for changes of portal venous blood flow and changes of extrahepatic arterial circulation. Thus normal hepatic arterial blood flow is the most important factor as far as prognosis of shunt operations is concerned. The manifestation of portal-systemic encephalopathy in addition depends not only upon the amount of portal-venous blood bypassing the liver, but also upon arterial blood flow, since urea synthesis is located primarily in zone 1 of liver microcirculation, which is supplied in the first line by the hepatic arterial system. Reduction of portal venous blood flow plays a rather minor role as compared to reduction of arterial flow; it does mean however a considerable loss of important nutritive and trophic factors for the liver.
mesh_terms: D000641:Ammonia / Q000378:metabolism; D006499:Hepatic Artery; D006501:Hepatic Encephalopathy / Q000378:metabolism; D006801:Humans; D008102:Liver Circulation; D008103:Liver Cirrhosis / Q000188:drug therapy; D008833:Microcirculation; D014508:Urea / Q000096:biosynthesis; D014667:Vasopressins / Q000627:therapeutic use
chemical_list: D014667:Vasopressins; D000641:Ammonia; D014508:Urea
vernacular_title: Normale und pathologische Leberdurchblutung -- Mechanismen und klinische Relevanz.