February, 1944 Gall-bladder Disease: Pathology the Clinical Pathology of Gall-bladder Disease

The chief function of the gall-bladder is to act as a reservoir for the bile secreted by the liver during the interdigestive period. This storage of bile is made possible by absorption of water, and the bile is thus concentrated three to ten times. Normally, the main biliary constituents, viz. bile salts, bilirubin, calcium and cholesterol, are not absorbed, but if the gall-bladder is obstructed these substances are absorbed differentially, and ultimately all disappear and are replaced by the mucus secreted by the organ. During the normal process of reduction in bile volume, an equalisation of pressure is effected in the biliary system, and the loss of this function is probably a factor in the dilatation of the ducts that usually occurs after cholecystectomy. The gall-bladder fills during the fasting state as the sphincter of Oddi is tonically contracted and the liver secretion of bile, although variable, is continuous. Following a meal, the passage of chyme from the stomach into the duodenum causes a relaxation in the tone of Oddi's sphincter and simultaneously the hormone cholecystokinin is liberated from the duodenal mucosa. The latter, after absorption into the bloodstream, stimulates the gall-bladder musculature to contract and to empty its contents into the duodenum. Fats, especially egg yolk and cream, are the most effective stimulus to cholecystokinin production, and hence for the emptying of the gallbladder. There is, therefore, a tendency to gall-bladder stasis if fats are absent from the diet and in pathological states, apart from acute cholecystitis, it would appear advisable to include as much fat in the diet as possible without producing pain. Absorption of the bile salts in the duodenum from the concentrated gall-bladder bile produces a choleretic action on the liver so that liver bile continues to be added to the duodenal contents throughout the digestion of the meal. Functional disturbances in the normal reciprocal action of relaxation of Oddi's sphincter and gall-bladder evacuation are now well recognised. Three main types of this disordered motor function (biliary dyskinesia) can thus be distinguished on a physiological basis.