Pancreas

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The pancreas is a dual-function gland, having features of both endocrine and exocrine glands.

A Endocrine Function

B Digestive (Exocrine) Function

C Pancreatic Bio-feedback Mechanisms

The part of the pancreas with endocrine function is made up of approximately a million cell clusters called Islets of Langerhans.

Four main cell types with different functions exist in the islets.

1. 
   a (alpha) cells secrete glucagon (increase glucose in blood)
2. 
   � (beta) cells secrete insulin (decrease glucose in blood)
3. 
   ? (delta) cells secrete somatostatin (regulates/stops a and � cells)
4. 
   PP cells, or gamma cells, secrete pancreatic polypeptide

1. 
   Pancreatic juice, composed of the secretions of both ductal and acinar cells
2. 
   Ductal cells produce bicarbonate (HCO3) - neutralise acidity of stomach contents entering the duodenum
3. 
   Acinar cells produce pancreatic enzymes (zymogens) that activate in the small bowel and break down proteins, fat, and DNA/RNA

Digestive Enzymes:

1. Trypsinogen, breaks down proteins into basic amino acids in the duodenum, activated by Trypsin
2. Chymotrypsinogen, breaks down proteins into other amino acids, activated by Trypsin
3. Carboxypeptidase also helps to break down proteins
4. Elastases that degrade the protein elastin and some other proteins
5. Pancreatic lipase that degrades triglycerides into fatty acids and glycerol
6. Sterol esterase
7. Phospholipase
8. Nucleases that degrade nucleic acids, like DNAase and RNAase
9. Pancreatic amylase breaks down most carbohydrates, inc starch and glycogen

1. 
   Secretin, a hormone from the duodenum that decreases gastric emptying, increases secretion of the pancreatic juices.
2. 
   Cholecystokinin (CCK), a peptide from the duodenum stimulates secretion of the pancreatic juices. CCK also increases gallbladder contraction, resulting in bile squeezed into the cystic duct, common bile duct and eventually the duodenum. Bile of course helps absorption of the fat by emulsifying it, increasing its absorptive surface. Bile is made by the liver, but is stored in the gallbladder.
3. 
   Gastric inhibitory peptide (GIP), from the duodenum, decreases gastric emptying.
4. 
   Somatostatin, a hormone from the duodenum and pancreas delta cells inhibits pancreatic juice production.

If the pancreas needs extra help, it will show as low digestive function and then digestive enzymes such as L&L Enzymes + from http://www.tiptop4life.co.uk are advised.