Pancreas Dr Ahrsia V F Department of Physiology

Pancreas Dr. Ahrsia V F Department of Physiology 2/2/19

Objectives • Functional anatomy of pancreas. • Pancreatic juice - Composition - Secretion - Regulation • Applied aspects

Functional anatomy of Pancreas

Pancreatic Juice • Volume : 500 to 800 m. L/day • Reaction : Highly alkaline with a p. H of 8 to 8. 3 • Specific gravity : 1. 010 to 1. 018

PROTEOLYTIC ENZYMES: 1. Trypsin: • Trypsinogen • Enterokinase, secreted by duodenal mucosa. • Autocatalytic action Trypsinogen Enterokinase Trypsinogen Trypsin Functions: • Protein Trypsin proteoses and polypeptides. • Activates other pancreatic enzymes.

2. Chymotrypsin : • Chymotrypsinogen • Activated by trypsin Chymotrypsinogen Trypsin Chymotrypsin. Function: • Hydrolyses proteins into small polypeptides

3. Carboxypeptidase A and B • Procarboxipeptidase A and B • Activated by enterokinase and trypsin. Function: • Carboxypeptidase A cleaves carboxy terminal amino acid with aromatic side chain • Carboxypeptidase B cleaves carboxy terminal amino acid with basic side chain. • Polypeptides to amino acids.

4. Elastase: • Proelastase • Activated by trypsin • Digests elastin. 5. Nucleases (ribonuclease and deoxyribonuclease) • Splits nucleic acid of RNA and DNA into nucleotides. 6. Collagenase: • Digests collagen

PANCREATIC LIPASES 1. Pancreatic lipase • Presence of bile salts and colipase enhances it activity. Lipids Pancreatic lipase glycerol + fatty acids. 2. Cholesterol ester hydrolase Cholesterol+ fatty acids. 3. Phospholipase A 2 • It converts Lecithin to Lysolecithin and Cephalin to Lysocephalin

4. Phospholipase B • It converts lysolecithin and lysocephalin to phosphoryl choline and free fatty acids. 5. Bile salt activated lipase • Weak lipolytic action

AMYLOLYTIC ENZYMES Pancreatic amylase: • Digests carbohydrates to form disaccharides Starch Pancreatic lipase Dextrin + maltose

Pancreatic juice secretion • Secretion of pancreatic enzyme: • Formation of aqueous part: Secretion of bicarbonate rich fluid by ductal epithelial cells.

Regulation of pancreatic juice secretion • Cephalic phase • Gastric phase • Intestinal phase

Applied aspects

Pancreatitis Inflammation 1. Acute pancreatitis 2. Chronic pancreatitis. Acute Pancreatitis • Heavy alcohol intake or gallstones. Features of acute pancreatitis: i. Severe upper abdominal pain ii. Nausea and vomiting iii. Loss of appetite and weight iv. Fever and Shock.

Chronic Pancreatitis • Repeated acute inflammation or chronic damage to pancreas. Causes : i. Longtime consumption of alcohol ii. Chronic obstruction of ampulla of Vater by gallstone iii. Hereditary iv. Congenital abnormalities of pancreatic duct v. Idiopathic pancreatitis Features: • Severe pain in upper abdominal region, which radiates to the back • Complete destruction of pancreas • Absence of pancreatic enzymes • Steatorrhea • Fever, nausea and vomiting • Tender and swollen abdomen • Weight loss.

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