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PANCREAS ANATOMY. esophagus. stomach. ductus choledocus. pancreas. duodenum. duct of. Santorini. duct of. Wirsung. PANCREATIC SECRETIONS. 1. PROTEASES (70%). Endopeptidases (trypsin, chymotrypsin, elastases). Exopeptidases (carboxypeptidases).
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PANCREAS ANATOMY esophagus stomach ductus choledocus pancreas duodenum duct of Santorini duct of Wirsung
PANCREATIC SECRETIONS 1. PROTEASES (70%) Endopeptidases (trypsin, chymotrypsin, elastases) Exopeptidases (carboxypeptidases) trypsinogen trypsin activates all other precursors enterokinase (duct walls) 2. NUCLEASES (DNAase, RNAase) 3. PANCREATIC AMYLASE (hydrolyse starch and gl;ycogen) 4. PANCREATIC LIPASE (triglycerides fatty acids and glycerol)
REGULATION OF SECRETION 1. SECRETIN food in release of release of secretin secretion of alkaline pH stomach stomach acid into blood by bicarbonate (ideal for into duodenum duodenal cells by duct cells pancreatic enzymes) 2. PANCREOZYMIN (cholecystokinen) amino acids and release of pancreozymin relase of pancreatic enzymes fats in intestine by intestinal mucosa into the intestine into blood 3. GASTRIN food in stomach gastrin secretion release of pancreatic enzymes into the intestine by stomach mucosa 4. AUTONOMIC INNERVATION (vagus nerve)
PANCREAS (PANORAMIC) islet of Langerhans pancreatic acini islet of pancreatic lobe Langerhans BV
PANCREATIC SECRETORY DUCTS LARGE SECRETORY DUCT INTERLOBULAR DUCT simple cuboidal epithelium acinus simple columnar epithelium
EXOCRINE PANCREAS pyramidal secretory acinus basal basophilia cell (rough ER) merocrine secretion (exocytosis) zymogen granules centro- condensing acinar golgi vacuoles cells vesicles blood vessel intercalated duct rough nerve golgi endoplasmic apparatus reticulum interlobular zymogen duct granules
INTERCALARY DUCTS AND CENTROACINAR CELLS intercalary duct centroacinar cell intercalary duct
PANCREATIC EXOCRINE SECRETORY CELL zymogen granules centroacinar cell
CELL BIOLOGY OF PANCREATIC SECRETION 1. SYNTHESIS 2. SEGREGATION mRNA for 14 C -leucine + tRNA chymotrysinogen ribosomes 14 mRNA C-amino-acyl tRNA ribosomes polypeptide chymotrysinogen RER cisterna 6. DISCHARGE 3. INTRACELLULAR TRANSPORT exocytosis RER transitional elements 5. INTRACELLULAR 4. CONCENTRATION STORAGE golgi zymogen apparatus H2O granules H2O golgi vesicles condensing vacuoles
EXPERIMENTAL METHODS IN CELL SECRETION 1. SUBCELLULAR FRACTIONATION 2. RADIOAUTOGRAPHY (grind and find) (cook and look) developed silver grains density photographic gradient vesicles emulsion centrifugation microsomes (RER) golgi condensing ultrathin vacuoles section zymogen pancreatic granules acinar cell (3 mins) (7 mins) (80 mins) cpm cpm cpm 14 C 14 14 C C leucine leucine leucine RER golgi cond zymogen RER golgi cond zymogen RER golgi cond zymogen pulse chase
ISLET OF LANGERHANS alpha cell (glucagon) vascular pole (secretion by exocytosis) acinus beta cell beta cell alpha (insulin) cell fenestrated capillary blood capillary INSULIN- increases membrane promotes glycogenesis decrease blood glucose levels permeability to glucose GLUCAGON - promotes glycogenolysis increases blood glucose levels “ ANTAGONISTIC HORMONES”
STAINED ALPHA AND BETA CELLS ALPHA CELLS BETA CELLS