Anatomy & physiology of pancreas


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Seminar on anatomy and physiology of Pancreas with emphasis on Surgically important aspects

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Anatomy & physiology of pancreas

  1. 1. Anatomy & Physiologyof the PancreasSanjay George
  2. 2. AnatomyDerived from ‘Pan’ – all ‘Kreas’ –flesh15-20cm long, 2.5 – 3.8cmbroad, 1.2 – 1.8cm thickWeighs 80gSituated in retroperitoneum
  3. 3. Contd..Divided:Head – 30%Body and Tail – 70%Head corresponds with the curve of duodenumoverlying the body of the 2nd lumbar vertebra andthe venacava.Aorta and superior mesenteric vessels lie behindthe neck.Near upper border of neck superior mesentericvein joins splenic vein to form portal vein.
  4. 4. Contd..Coming of side of pancreatic headand passing to the left and behindsuperior mesenteric vein is uncinateprocess.Tip of pancreatic tail extends upto thesplenic hilum.
  5. 5. Histology80-90% of pancreatic tissue – Exocrine acinar tissueorganised as lobulesPancreatic duct Interlobular & Intralobular ductsductules aciniMain duct – Columnar cellsDuctules – Cuboidal cellsAcinar cells clumped around central lumen whichcommunicates with duct system.
  6. 6. HistologyClusters of endocrine cells distributed throughout calledIslets of LangerhansIslet:75% - B Cells – Insulin20% - A Cells – Glucagon5% - D Cells – SomatostatinSmall number of pancreatic polypeptide cellsB cells form inner core surrounded by other cells.Capillaries draining islet cells drain into portal vein.
  7. 7. Blood SupplyArterial:Pancreatic Branches of splenicarterySuperior pancreaticoduodenal arteryInferior pancreaticoduodenal arteryVenous:Drain into splenic, superiormesenteric and portal veins
  8. 8. LymphaticsHead & Neck – PancreaticoduodenalBody & Tail - Pancreaticosplenic
  9. 9. Nerve SupplyParasympathetic – VagusSympathetic – plexuses aroundits arteries
  10. 10. EmbryologyTime Event1 Day 26 Dorsal Pancreatic duct arises from dorsal side ofduodenum2 Day 32 Ventral Bud arises from base of hepatic diverticulum3 Day 37 Contact occurs between the 2 buds. Fusion by end of 6thweek4 Week 6 Ventral bud produces the head and uncinate process5 Week 6 Ducts Fuse6 Week 6 Ventral duct and distal portion of dorsal duct form themain duct7 Week 6 Proximal duct forms the duct of Santorini8 Month 3 Acini appear9 Months 3-4 Islets of Langerhans Appear & become active
  11. 11. EmbryologyMalrotation of ventral bud in 5th week –annular pancreas.Mode of ductule fusion in 7th weekproduces various possible ductularpatterns.Anatomy of main duodenal papilla –ampulla of vater is also variable.
  12. 12. PhysiologyIn response to food – secretes digestiveenzymes in an alkaline bicarbonate richfluid.Secretion enhanced by:SecretinCholecystokininVagal StimulationWithin cells enzymes are in inactive form.
  13. 13. Pancreatic Secretions Electrolytes: Cations: Na+, K+, Ca2+, Mg2+, Zn2+ Anions: HCO3-, Cl- and traces of SO42-, HPO42- Enymes: Pancreatic alpha-amylase Pancreatic lipase Pancreatic esterase Pancreatic pro-phospholipase A2 Pancreatic proteolytic enymes: Trypsinogen Chymotrypsin Pro – carboxypeptidase A and B Ribonuclease Deoxy-ribonuclease Pro-elatase Trypsin inhibitor
  14. 14. Contd..Hormones:InsulinGlucagonSomatostatin
  15. 15. Total Removal of PancreasDiabetes mellitus due to pancreaticendocrine deficiency of insulinnDevelopment of digestive disturbances:Increase of faecal fats – bulky, foulsmelling, pale and greasy stoolsIncreased faecal nitrogen due toincomplete proteolysisNo abnormality of carbohydrate digestionPancreatic insufficiency – loss of 30% ofcalorific value of ingested food.