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The Pancreas
The pancreas is a soft, pinkish-gray gland; it is an elongated organ (12-16 cm long) that lies behind the stomach transversely. It has a head portion that sits to the right of the body by the duodenum and the tail portion that ends closely to the spleen that is on the left side of the body. The main function of the pancreas is the production and release of several enzymes and two major hormones. The pancreas has two major types of tissue: The acini, which secrete digestive juices (enzymes) into the duodenum (upper portion of the small intestines) and the islets of Langerhans, which secrete insulin and glucagon.
The enzymes secreted are trypsin, chymotrypsin (these breakdown proteins into peptide particles), carboxypolypeptidase (splits peptides into amino acids, the building blocks of life), nuclease (nucleic acids), elastase (involved in certain peptide digestion), amylase (breaks down starches, glycogen, and other carbohydrates), lipase (breaks down fat into fatty acids), cholesterol esterase (breaks down cholesterol esters), phospholipase (splits fatty acids away from phospholipids). This is the basic principle of the enzymes; it really goes into much greater depth on the formation, activation and deactivation of the above enzymes.
The islets of Langerhans consist on average of 1–2 million cells. It has three major types of cells called the alpha, beta, and delta cells. The alpha cells account for about 25 –30 % of glucagon secretion. Glucagon is secreted in response to low blood sugar (hypoglycemia). It causes the release and new formation of glucose by the liver. Another factor that can cause the relief of glucagon is by the growth hormone from the anterior pituitary gland. The beta cells account for 60-65% of insulin secretion. Insulin is secreted in direct response to the intake of glucose (sugars/carbs) that we eat. Insulin is responsible for storing the excess energy in the muscles and liver. It is also responsible for the fat storage in adipose (fat) tissue, inhibits the breakdown of proteins in the cells, promotes amino acid uptake by the cells in the body (for growth), and plays a role in several different other functions in the body. The delta cells account for 10% of somatostatin secretion. This is an inhibiting hormone (this is like the brakes on a car). It inhibits the release of growth hormone, thyrotropin, insulin, glucagon, gastrin, rennin and corticotropin.