PHYSIOLOGICAL AND PATHOLOGICAL RESPONSES IN THE BLOOD‐VESSELS OF THE LIVER

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Abstract
The circulation in the intact liver and its reaction to various stimuli were studied in frogs, mice and rats by a modification of Knisely's transillumination technique.Characteristic patterns in the anatomy and distribution of the portal and hepatic veins are described. Sinusoids appear as thin‐walled collapsible tubes with complete linings. Arteriovenous anastamoses are frequent, and reconcile the rarity of infarcts from embolism with the frequency of pyæmic abscesses and metastatic deposits. The behaviour of circulating dyes and toxic agents suggest the presence of functional zones in the liver lobule. Certain structural differences, too, are noticed in the centrilobular areas.Under normal conditions the liver circulation shows an irregularly intermittent rhythmicity. Blood‐flow is under sympathetic control, but there is no evidence of a parasympathetic supply. A chemical control is suggested by the effects of hormones such as adrenalin, acetylcholine and histamine, while respiration has a very definite influence.Stimuli such as obstruction of the vessels, mechanical trauma, hæmorrhage, heat and cold induce rapid responses in the liver circulation. Indeed the centrally important observation is the readiness with which it reacts to stimuli, and this may have a significant bearing on the pathogenesis of liver diseases.