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Physiology of the Human Biliary System
Published in Wenguang Li, Biliary Tract and Gallbladder Biomechanical Modelling with Physiological and Clinical Elements, 2021
Bile is synthesised in the liver and excreted into the lumen of the duodenum when a fatty meal or any other sort of meal is consumed, or even water is drunk. Bile consists mostly of water with minor amount of ions, bilirubin (a pigment derived from haemoglobin), cholesterol and an assortment of lipids – the bile salts. The water and ions assist in the dilution and buffering of acids in chyme as it enters the small intestine. The large and water-soluble drops, containing a variety of lipids, are created by mechanical processing in the stomach. The enzymes from the pancreas are not lipid-soluble; consequently, they only interact with lipids at the surface of the lipid drop. Bile salts break the large lipid drops apart. The tiny droplets, with coating of bile salts, increase the surface area available for enzymatic attack. Furthermore, the layer coated by bile salts allows the interaction between the lipids and enzymes to be easier. After lipid digestion has been completed, bile salts promote the absorption of lipids by the intestinal epithelium. More than 90% of the bile salts are themselves reabsorbed primarily in the ileum as lipid digestion is finished. The reabsorbed bile salts enter the hepatic portal circulation and are collected and recycled by the liver (Martini 2001).
Telescopes for Inner Space: Fiber Optics and Endoscopes
Published in Suzanne Amador Kane, Boris A. Gelman, Introduction to Physics in Modern Medicine, 2020
Suzanne Amador Kane, Boris A. Gelman
The gallbladder stores bile produced by the liver and resecretes it when needed into the small intestine, thus aiding in the digestion of fatty foods. In some persons, cholesterol crystals, called gallstones, form within the gallbladder. Large ones can potentially block the bile ducts and cause sharp pains in the abdomen. Sometimes medication alone can dissolve these gallstones. Failing this treatment, persons suffering from this can live with occasional abdominal pain while maintaining a restricted low fat diet, or they can undergo surgery to have their gallbladder removed, an operation called cholecystectomy. In spite of the often acute abdominal pain, many persons once opted to live with the condition indefinitely when faced with the prospect of open surgery, which typically entails a one-week hospital stay, an extended recovery period lasting an average of six weeks, and a six-inch-wide surgical scar.
Liver and biliary system, pancreas and spleen
Published in A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha, Clark’s Procedures in Diagnostic Imaging: A System-Based Approach, 2020
A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha
ERCP/MRCP. The traditional test for imaging the extrahepatic bile ducts was endoscopic retrograde cholangio-pancreatography (ERCP). This involves passing a special endoscope into the duodenum and cannulating the distal CBD via the ampulla of Vater, in order to opacify the biliary system by retrograde injection of iodinated contrast medium. The biliary system is then imaged using fluoroscopy. This technique allows very accurate demonstration of the biliary anatomy and accurately detects stones and strictures (benign and malignant). It also permits stone extraction and/or stenting at the same procedure, but it is invasive and can have significant complications including bile duct perforation and cholangitis (infection).
Physicochemical and spectral evaluation of the interactional behavior of nicotinic acid (vitamin B3) with mixed [sodium deoxycholate (bile salt) + cetyltrimethylammonium bromide] surfactants
Published in Journal of Dispersion Science and Technology, 2021
Parampaul K. Banipal, Pallavi Sohal, Tarlok S. Banipal
Bile salts execute vital physiological functions throughout the digestion of food. Sodium deoxycholate (SDC, anionic steroidal bio-surfactant) is bio-synthesized in liver and is then stored in gall bladder. It is a facial amphiphile having hydroxyl (−OH) groups on the polar face and the methyl (−CH3) groups on the non-polar face.[2,3] SDC undergoes aggregation in aqueous solution mainly due to the hydrophobic interactions among the apolar groups and hence their hydrophobic core can solubilize fat-soluble vitamins, cholesterol, fatty acids, lipids, monoglycerides, and hydrophobic medicinal ingredients.[4] Additional cholesterol from liver is transported to intestine through their micelles, thus allowing the excretion of cholesterol from human body.[5] Moreover, bile salts have been proposed to be used as a better surfactants as compared to alkyl sulfates, that is, sodium dodecyl sulfate for the analysis of vitamins and vitamin cofactors. Also, SDC boosts the permeation of drug through the biological membranes.[6–9]
Toxigenic gut bacteria, diet and colon carcinogenesis
Published in Journal of the Royal Society of New Zealand, 2020
Jacqueline I. Keenan, Frank A. Frizelle
Fat is another macronutrient found in red meat and diets high in saturated fat promote changes in host bile acid composition (Devkota et al. 2012), as illustrated by significantly higher levels of dietary fat intake and secondary faecal bile acids in African Americans when compared to native Africans (O’Keefe et al. 2015). In contrast, switching to a high-fibre, low-fat diet suppresses secondary bile acid synthesis and instead increases butyrogenesis (O’Keefe et al. 2015). Intriguingly, adding bile salts to cultured B. fragilis results drives biofilm formation (Pumbwe et al. 2007) whereas butyrate indirectly mitigates the effect of the B. fragilis toxin by upregulating expression of the E-cadherin protein (Barshishat et al. 2000). The possibility that butyrate may also have a direct role in regulating bft expression remains to be determined (Sun and O’Riordan 2013).
Another target organ?
Published in Archives of Environmental & Occupational Health, 2019
The route of exposure of most obvious concern is clearly oral and there are an abundance of ways that a food or water contaminant, a food additive or residue, or an inhaled and aspirated material might reach and affect the gut microbiome. Of course, they would have to get through the stomach and its acidity first. The stomach is normally almost sterile (in adults), except in serious disease and Helicobacter pylori infection. Once beyond the pylorus, however, there is little to impede further growth and the reservoir for the microbiome appears to be the cecum, a sac at the transition from the small intestine to the colon, where the appendix lies. Many xenobiotics are metabolized in the liver and excreted in bile, both organic compounds and metals. Many of these are of toxicological interest, such as organochlorine compounds and mercury. Iron, important in the inflammatory response, has long been known to be concentrated in bile.4 The common bile duct carries the secreted bile to the duodenum, the first part of the small intestine, just downstream from this transition. At this point, xenobiotics concentrated from the circulation meet the microbiome by a route independent of ingestion.