胰臟分兩個塊：胰腺和胰島。

胰腺分泌胰液，包含多種消化酶。

胰島的阿爾法細胞分泌胰高血糖素，促進肝糖原分解，使血壓升高。

貝塔細胞分泌胰島素，促進肝糖原的合成，使血壓降低。

The pancreas is an organ that lies beneath the stomach. It"s nestled in a loop formed by the first portion of the small intestine. It"s a dual-purpose organ, having both exocrine and endocrine functions.

As an exocrine gland, it produces enzymes and sodium bicarbonate essential for the digestion of foodstuffs in the small intestine. They flow into the small intestine by a duct called pancreatic duct.

Its endocrine function is fulfilled by special cells that produce hormones such as insulin and glucagon that help regulate blood glucose level, thus assisting in maintaining homeostasis.

The digestive enzymes of the pancreas flow through the large pancreatic duct into the duodenum. Each day, approximately 1200~1500 ml of pancreatic juice is produced and released into the small intestine. This liquid is composed of water, sodium bicarbonate, and several digestive enzymes as follows:

Trypsin: cleaves peptide bonds of polypeptides and proteins.

Chymotrypsin: cleaves peptide bonds of polypeptides and proteins.

Carboxypeptidase: cleaves peptide bonds on carboxyl end of polypeptides.

Amylase: breaks starch molecules into smaller units (i.e. maltose).

Phospholipase: cleaves fatty acids from phosphoglycerides to form monoglycerides.

Lipase: cleaves 2 fatty acids from triglycerides

Ribonuclease: breaks RNA into smaller nucleotide chains.

Deoxyribonuclease: breaks DNA into smaller nucleotide chains.

Sodium bicarbonate neutralizes the acidic chyme released by the stomach and thus protects the small intestine from stomach acid. It also gives the pancreatic juice a pH of about 8, creating an environment optimal for the function of the pancreatic enzymes.

The pancreatic enzymes released into the small intestine act on the large food molecules, i.e. proteins, starches, etc. As a result of pancreatic enzymatic activity, fats, proteins, and carbohydrates are broken down into smaller molecules.

The pancreas secretes its enzymes in an inactive form. This protects the gland from self-destruction. Trypsinogen, for example, is the inactive form of the protein-digesting enzyme trypsin. Produced by the pancreas, trypsinogen is activated by a substance on the epithelial lining of the small intestine. Trypsin, in turn, activates other digestive enzymes.