IM 6 Finals Gallbladder & Pancreatic Diseases PDF

BILE SECRETION AND COMPOSITION BILE ACIDS ENTEROHEPATIC CIRCULATION SPHINCTERIC FUNCTIONS...

BILE SECRETION AND COMPOSITION BILE ACIDS ENTEROHEPATIC CIRCULATION SPHINCTERIC FUNCTIONS CONGENITAL ANOMALIES Bile- formed in hepatocytes and secreted into a network of A. Primary bile acids Unconjugated bile acids- absorbed throughout the gut by passive -during fasting, the sphincter of Oddi (SOD) maintains high Can affect number, size, and shape. canaliculi, ductules, and ducts. -synthesized in the liver from cholesterol. diffusion pressure, preventing duodenal reflux and promoting gallbladder -then conjugated with glycine/taurine and secreted into bile. filling. Agenesis of the Gallbladder (number) Gallbladder- alters bile composition by reabsorbing inorganic Conjugated bile acids- actively transported in the distal ileum. -gallbladder is absent anions, chloride, and bicarbonate (concentration) -cholic acid Cholecystokinin (CCK) -chenodeoxycholic acid Reabsorbed bile acids enter the portal vein, are taken up by -released from the duodenum in response to fat and amino acid Duplications, Rudimentary, Giant Gallbladders (shape and size) Major compositon: hepatocytes, reconjugated, and resecreted into bile, forming the ingestion -bile acids (80%) B. Secondary bile acids enterohepatic circulation. 1 contracts the gallbladder Phrygian cap (shape) -phospholipids (16%) - formed in the colon by bacterial metabolism of primary bile acid 2 reduces SOD resistance -fundus is separated from the body of the gallbladder by a fold or septum, partially or completely. -cholesterol (4%) -bile acid pool (2–4 g) cycles 5–10 times daily 3 enhances bile flow into the duodenum. -deoxycholate -with 95% reabsorption efficiency. -lithocholate (poorly absorbed in colon) -daily fecal bile acid loss (0.2–0.4 g) balanced by hepatic synthesis -ursodeoxycholate (stereoisomer of chenodeoxycholic acid). to maintain the pool size. 1 Above ~2mM, forms micelles, aiding in cholesterol solubility and fat absorption 2 Drive hepatic bile flow and water and electrolyte transport in the intestines 3 Helps in biliary excretion and absorption of cholesterol, fat- soluble vitamins 3 Acts as hormones, binding to nuclear and G protein-coupled receptors that regulate bile acid metabolism and enterohepatic circulation. GALLSTONES/CHOLELITHIASIS EPIDEMIOLOGY PATHOGENESIS BILIARY SLUDGE BILIARY COLIC DIAGNOSIS TREATMENT -Western countries Formation of Lithogenic bile: -thick, mucous substance composed of -severe, steady ache or fullness in the epigastrium or RUQ ULTRASONOGRAPHY A. Medical Therapy -Formation increases after age 50. 1. Increased biliary cholesterol secretion- major factor 1 lecithin-cholesterol liquid crystals, -radiates to the interscapular area, right scapula, or shoulder -highly accurate in detecting gallstones 1. Ursodeoxycholic Acid (UDCA) -Women have a higher prevalence than men across all ages. -with obesity, metabolic syndrome, high-calorie and high- 2 cholesterol monohydrate crystals -usually 30 mins - 5 hours; if beyod 5 hours = acute cholecystitis -can detect stones as small as 1.5 mm in diameter. -limited to radioluscent stones