Themain pancreatic duct runs along thegland from thetail tothe head, before entering theduodenum,whereit joinsthecommonbileductattheampulla of Vater.Theaccessorypancreaticductenterstheduodenumat2~2.5cmproximal totheampullaofVater.TheampullaofVaterisoftenlocatedbehind the inner wall of themiddle of the second segment of the duodenum,about7~1Ocmfromthepylorus.Itisthe junctionof thebile duct,pancreaticduct anddigestivetract,[4] andhasimportantfunctions.(Common)bileduct-PancreaticnotchPancreaticduct茶(ofWirsung)ccessorypancreaticduct(ofSantorini)[4] From Lehman, Feldman' s GastroAtlas Online
The main pancreatic duct runs along the gland from the tail to the head, before entering the duodenum, where it joins the common bile duct at the ampulla of Vater. The accessory pancreatic duct enters the duodenum at 2~2.5cm proximal to the ampulla of Vater. The ampulla of Vater is often located behind the inner wall of the middle of the second segment of the duodenum, about 7~10cm from the pylorus. It is the junction of the bile duct, pancreatic duct and digestive tract, and has important functions. [4] From Lehman, Feldman’s GastroAtlas Online. [4]
Physiology-Exocrine FunctionTheexternalsecretionofthepancreasconsistsofaclear,alkaline(pH7.0-8.3)solutionof1-2L/dcontainingdigestiveenzymes.Thewaterandelectrolytesecretionisformedbythecentroacinarandintercalatedductcellsprincipallyinresponsetosecretinstimulation.Pancreaticenzymesaresynthesized,stored(aszymogengranules),andreleasedbytheacinarcellsofthegland,principallyinresponsetocholecystokininandvagalstimulationTurnoverofprotein inthepancreas exceedsthatof anyotherorgan inthebody.Intravenously injectedaminoacidsareincorporatedintoenzymeproteinandmayappearinthepancreaticjuicewithin1hour.Threemechanismspreventautodigestionofthepancreasbyitsproteolyticenzymes:(1)Theenzymesarestored in acinar cellsaszymogengranules, wheretheyare separated fromother cell proteins.(2)Theenzymesaresecreted inan inactiveform.(3)Inhibitorsofproteolyticenzymes arepresentinpancreatic juiceandpancreatictissue
Physiology——Exocrine Function The external secretion of the pancreas consists of a clear, alkaline (pH 7.0-8.3) solution of 1-2 L/d containing digestive enzymes. The water and electrolyte secretion is formed by the centroacinar and intercalated duct cells principally in response to secretin stimulation. Pancreatic enzymes are synthesized, stored (as zymogen granules), and released by the acinar cells of the gland, principally in response to cholecystokinin and vagal stimulation. Turnover of protein in the pancreas exceeds that of any other organ in the body. Intravenously injected amino acids are incorporated into enzyme protein and may appear in the pancreatic juice within 1 hour. Three mechanisms prevent autodigestion of the pancreas by its proteolytic enzymes: (1) The enzymes are stored in acinar cells as zymogen granules, where they are separated from other cell proteins. (2) The enzymes are secreted in an inactive form. (3) Inhibitors of proteolytic enzymes are present in pancreatic juice and pancreatic tissue
Physiology-Exocrine FunctionIn the non-digested period,pancreaticjuice is secreted little orSight, Smell,no.After eating,pancreaticjuiceChew,FoodCause watery secretionbegins to secrete. Therefore, food isCausesthesecretionofenzymesCentralnervousanaturalfactorthatstimulatestheAfferentfibersofEfferentfibersofsecretionofpancreaticjuice.Whenthe vaqal nervethevaqal nerveeating,pancreaticjuice is controlledexpansionby nerves and bodyfluids, but it isGastric bodyPancreaGastricantrumexpansiorProteinbreakdownproductsmainlycontrolledbybodyfluids.CCKSecretinPancreatic juice is mainly secretedSmallintestineandregulatedbythestimulationof..1secretin,cholecystokinin(CCK)andHCIDigestionproducts ofBacktrackprotein and fatthe vagal nerve
In the non-digested period, pancreatic juice is secreted little or no. After eating, pancreatic juice begins to secrete. Therefore, food is a natural factor that stimulates the secretion of pancreatic juice. When eating, pancreatic juice is controlled by nerves and body fluids, but it is mainly controlled by body fluids. Pancreatic juice is mainly secreted and regulated by the stimulation of secretin, cholecystokinin (CCK) and the vagal nerve. Physiology——Exocrine Function
Physiology-Endocrine FunctionThe function of theendocrinepancreasistofacilitatestorageoffoodstuffsTable Variouspancreaticendocrinehormonesandtumorsby release of insulin after acell%Endocrinetumorshormonemealandtoprovide a(cell)mechanismfortheir20%insulinInsulinomaamobilization byrelease ofβ70%GlucagonGlucagonomaglucagon during periods of85%SomatostatinSomatostatinomafasting.InsulinandglucagonGGastrinGastrinoma (ZES)Lowas well as pancreaticD2VIPVIPoma/WDHALowpolypeptide andsomatostatinare produced by the islets ofLangerhans
Physiology——Endocrine Function The function of the endocrine pancreas is to facilitate storage of foodstuffs by release of insulin after a meal and to provide a mechanism for their mobilization by release of glucagon during periods of fasting. Insulin and glucagon, as well as pancreatic polypeptide and somatostatin, are produced by the islets of Langerhans. cell hormone Endocrine tumors % （cell） α insulin Insulinoma 20% β Glucagon Glucagonoma 70% δ Somatostatin Somatostatinoma 5% G Gastrin Gastrinoma（ZES） Low D2 VIP VIPoma/WDHA Low Table Various pancreatic endocrine hormones and tumors
Annular PancreasAnnularpancreasis a rarecongenitalcondition inwhicha ringofpancreatictissuefromtheheadofthepancreassurroundsthedescendingduodenum.Theabnormalityusuallypresentsininfancyasduodenalobstructionwithpostprandialvomiting.ThereisbileinthevomitusiftheconstrictionisdistaltotheentranceofthecommonbileductX-raysshowadilatedstomachandproximalduodenum(doublebubblesign)andlittleornoairintherestofthesmallbowelAftercorrectionoffluidandelectrolyteimbalance,theobstructedsegmentshouldbebypassedbyaduodenojejunostomyorothersimilarprocedure.Noattemptshouldbemadetoresectthe obstructingpancreas,becauseapancreaticfistulaoracutepancreatitisoftendevelopspostoperatively.Occasionally,annularpancreaswillpresentinadultlifewithsimilarsymptoms.[5] Eienne D, John A, Menias CO, Ward R, Tubbs RS, Loukas M.Annular panreas:areview ofits molecular embryology,genetic basis and clinical considerat ions.Ann Anat,2012 Sep;19(5)422-8. do10.1016/j.aanat.2012.04.006,Epub 2012 May 17
Annular Pancreas Annular pancreas is a rare congenital condition in which a ring of pancreatic tissue from the head of the pancreas surrounds the descending duodenum. The abnormality usually presents in infancy as duodenal obstruction with postprandial vomiting. There is bile in the vomitus if the constriction is distal to the entrance of the common bile duct. X-rays show a dilated stomach and proximal duodenum (double bubble sign) and little or no air in the rest of the small bowel. After correction of fluid and electrolyte imbalance, the obstructed segment should be bypassed by a duodenojejunostomy or other similar procedure. No attempt should be made to resect the obstructing pancreas, because a pancreatic fistula or acute pancreatitis often develops postoperatively. Occasionally, annular pancreas will present in adult life with similar symptoms. [5] Etienne D, John A, Menias CO, Ward R, Tubbs RS, Loukas M. Annular pancreas: a review of its molecular embryology, genetic basis and clinical considerat ions. Ann Anat. 2012 Sep;194(5):422-8. doi: 10.1016/j.aanat.2012.04.006. Epub 2012 May 17