fat, protein, and carbo- — Mark E. Lowe, § Michael Wilschanski Volume 61, Number 1, July 2015 )-rich fluid, which neutralizes gastric 3 Mike Thomson, exchanger. In distal ducts, however, where STEATORRHEA JPGN 3 /HCO David Hughes, the inability to digest fat leads to steatorrhea, the main PANCREATIC INSUFFICIENCY AND — Pancreatic enzymes are synthesized in the pancreatic acinar Bicarbonate is secreted by the pancreatic ductal epithelium. Exocrine pancreatic insufficiency (EPI) is defined as reduced 10% of the total pancreatic enzyme output (4). Pancreatic < Jeremy Screws, 4. The other major digestive lipase, gastric lipase, cannot fully EPORT jj Proteolytic proenzymes, or zymogens,tidase, are which activated is by localized enteropep- inproximal the jejunum brush border (1). oftrypsinogen the The to duodenum and activation trypsinentire results of cascade in the of the principle zymogensenzymes subsequent (2). zymogen are activation In secreted of2.5 adults, daily the L 6 into of to bicarbonate the 20 (HCO duodenum g along of with digestive about Throughout development, the pancreaswith the maintains biliary ductal a system and closethe the main relation main pancreatic duct such pancreatic that duodenum duct at and the same common location bile via duct thecells, empty ampulla of into stored Vater the (Fig.secreted in 1). into secretory thepeptides, and vesicles duodenum amino acids. Secretion in as is(CCK) mediated response by inactive and cholecystokinin to secretin, zymogens, luminalcells, peptide respectively, fatty in hormones and the released acids, mucosal epithelium by of the I small cells intestine. and S acid and provides an optimum pH for pancreaticSecretin enzyme is function. the main stimulantthus of it fluid and mediates bicarbonateSecretion the release, and is flow regulated ofductance by pancreatic regulator juice the (CFTR). into cystic Theactively the fibrosis generated transported into bicarbonate duodenum. transmembrane the ion ductal con- lumenpassive is together movement also with of sodium water and intoof the pancreatic duct, fluid which into facilitates the thethe small flow intestine. proximal Bicarbonate secretion pancreatic in which ducts is a is CI largely mediated by SLC26A6, pancreatic enzyme and bicarbonate secretion, orin both, which the results malabsorptiondigest of nutrients. all Although of pancreatic enzymes the 3 macronutrients the luminal bicarbonate concentrationbicarbonate is secretion already is high, mediated mostthe by of CFTR bicarbonate the (3). conductance via triglycerides, are deesterifiedup by pancreatic lipases,lipase easily which and make irreversibly< degraded when the luminalcompensate pH drops for the absenceenzymes, of particularly pancreatic pancreatic lipase.protein triglyceride In lipase 2 infants, (PTL)-related other enzymes and secreted bile fromto salt-stimulated the achieve lipase pancreas efficient that (BSSL), fat act are absorption with (5). the gastric BSSL lipase key is also present in hydrates clinical symptom of EPI. Fats, mainly ingested as long-chain R Sohail Z. Husain, and § Karoly Horvath, z LINICAL St Christo- Ghent Uni- C y ô Arnold Palmer z Abrahim I. Orabi, § Kathy Chen, y Children’s Hospital of Pitts- Beatrix Children’s Hospital, Henkjan J. Verkade, § # # to view instructions, documentation, and ¨ppi M, Thapar N, Orel R, Heuschkel R, Hadassah-Hebrew University Medical Center, Devendra Mehta, z OF THE PANCREAS . H.J.V. is a consultant for Friesland and Danone, has a http://www.naspghan.org/content/59/en/Continuing- ´ exocrine pancreatic insufficiency, nonstimulatory PFTs, 2015 by European Society for Pediatric Gastroenterology, ANATOMY AND PHYSIOLOGY Sheffield Children’s Hospital, Sheffield, UK, the Christopher J. Taylor, #
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