OVERVIEW
The pancreas is a complex large lobed flat gland. The lobes are called: the head; the middle; and the tail. The head connects to duodenum the entry into the small intestine. The pancreas secretes the hormones insulin and glucagon to regulate blood glucose levels. Additionally it secretes enzymes that aid in the digestion of fats and proteins in the small intestine. The pancreas is both an endocrine gland and an exocrine gland. The endocrine portion constitutes roughly 2% of the total mass of the pancreas, the rest being the exocrine part. Exocrine glands secrete directly to a duct. Endocrine glands secrete hormones directly to the blood stream. The bile duct from the liver is shared with the duct from the exocrine pancreas, which connects to the small intestine.
This discussion of the pancreas is not intended to be an in-depth treatment of the subject. This would require a much longer article and involve much additional discussion. The intent here is to provide an introduction and overview of the pancreas, its many constituent parts, the functionality of these parts, how it affects upon your health, and the diseases, which may affect the pancreas and the resultant effects upon your life.
The pancreas is a vital organ and is very necessary for your good health. Take good care of it. Feed it well and treat it kindly and you will be rewarded with a long and healthy life.
PANCREATIC CELL FUNCTION
The pancreas performs several important tasks: The regulation of the level of blood glucose at all times; The control of the various organs in the body that govern appetite, the emptying of the stomach, the rate of absorption of glucose from the small intestine; The stimulation and suppression of hormone output; and several other functions which will not be covered in this discussion. The insulin producing tissue of the Pancreas is called the Islets of Langerhans. The Beta Cell, which produces the insulin, is the most numerous of the cells in the Islets of Langerhans, comprising from 60% to 80% of all the cells in each Islet.
There are several different types of cells that comprise these Islets, these are:
Alpha: Produce glucagon, which raises the level of blood glucose
Beta: Produce insulin and amylin, which lower the level of blood glucose
Delta: Produce somatostatin. which inhibits the release of specific hormones
Gamma: Produce a polypeptide, which reduces the appetite
PP: Produce a 36 amino acid pancreatic polypeptide
D Cell: Types D1, D2, and D3
The substances produced by these cells are explained here:
Glucagon: A polypeptide of 29 amino acids. Glucagon stimulates the conversion of glycogen into glucose in the liver (glycogenolysis). It also converts fat and protein into intermediate metabolites, which eventually are converted to glucose (gluconeogenesis).
The secretion of glucagons is triggered by low levels of blood glucose, inhibited by high levels of blood glucose, and inhibited by amylin. Glucagon regulates the level of blood glucose between meals.
Insulin: Regulates the metabolization of carbohydrates in the blood, as well as affecting the metabolization of fats, and how the liver manages glucagon.
Amylin: A peptide comprised of 37 amino acids. The functions of Amylin:
Inhibits the secretion of glucagons; Slows the emptying of the stomach;
Sends a signal to the brain that curbs hunger.
Somatostatin: Comprised of two polypeptides, one of which is comprised of 14 amino acids and the other comprised of 28 amino acids. Somatostatin reduces the rate of absorption of food from the contents of the small intestine. Somatostatin is secreted by the hypothalamus and the small intestine as well.
Pancreatic Polypeptide: This peptide is secreted by the PP cells in the endocrine portion of the pancreas, mostly in the head of the pancreas. It is a peptide comprised of 36 amino acids. Pancreatic polypeptide is a cholecystokinin antagonist. It suppresses pancreatic secretion and stimulates gastric secretion.
These secretions are increased by: a meal of protein; acute hypoglycemia; a fast; or exercise. These secretions are decreased by somatostatin and the presence of blood glucose.
DISEASES OF THE PANCREAS
There are some serious diseases, which affect the pancreas and your health. These are described here.
Pancreatitis
Is an inflammation of the pancreas and is very painful. Pancreatitis has several etiologies, and can be either acute or chronic. It is either hereditary or acquired. Pancreatitis can be fatal.
Pancreatic Cancer
Is the fifth leading cause of cancer deaths worldwide and has a high rate of human mortality.
Type I Diabetes
When insulin production is severely reduced Type 1 Diabetes occurs. Blood glucose levels are uncontrolled.
Type II Diabetes
Insulin production is normal, but the insulin receptors no longer respond correctly.
Cystic Fibrosis
This is a genetic disorder causing the body to produce thick mucus that interferes with both respiratory function and the exocrine system. The mucus blocks the pancreas ducts, preventing digestive enzymes from reaching the small intestine which result in impaired digestion and causes malnutrition.
Damage to Mitochondrial DNA (mtDNA)
The free radical Nitric Oxide (NO) is able to damage mitrochondrial DNA, within the Beta Cells within the Islets of Langerhans. When damaged, diabetes may result. This is a recent discovery and has not been sufficiently corroborated. However, it is very likely that this could be one of the etiologies of diabetes.
DISCUSSION
Insulin production by the beta cells results from physiological stimulation. The beta cells promote insulin biosynthesis by causing insulin gene transcription by means of autocrine signaling. Autocrine means self-stimulation by the beta cell.
The D cells referenced earlier - are a rather new discovery - and have not yet been fully explored. However, there is much data to show that over-expression of some of these D cells, may be responsible for pancreatic cancer, as well as the resistance of these cancerous cells to chemotherapy and other treatments. Research has shown that over expression of cyclin D1 may contribute to chemo resistance of pancreatic cancer cells. This because cyclin D1 both promotes cell proliferation and inhibits drug-induced apoptosis (cell death).
The Cyclins (D1, D2, and D3) may play a part in the cause of Diabetes. Thus, proper regulation of these cyclins, may lead to the prevention of or the cure for Diabetes.
These last two cell types the PP cells and the D cells are not completely understood. On going research will provide more information regarding their functions and their role in the functioning of the pancreas.
DIETARY CONSIDERATIONS and HEALTH MAINTENANCE
In order to maintain good pancreatic health, it is necessary that you eat foods and take vitamin supplements, which contain antioxidants to ward off attacks by free radicals - namely Nitric Oxide (NO) and to provide the necessary chemicals such as folic acid and folate are able to provide. These supplements are found in vitamin B9.
CURRENT RESEARCH
There is much current research in the area of Molecular Endocrinology. This includes the pancreas and its many functions. Search the web using the argument "Molecular Endocrinology".
CONCLUSIONS
To maintain good health and to live a productive life to your hereditary limits, it behooves you to eat the right foods and supplements to prevent attacks by free radicals and to keep your all important mitochondria happy and well fed, those that live in your pancreas and the others that live all over your body. Be kind to your mitochondria - else they will do great harm to your health.
CITATIONS
2. A short description of Insulin Resistance
4. This report from PubMed, which is quite technical, discusses the subject of Insulin Resistance.
6. Finally, one last report on the possible regeneration of the pancreatic Beta Cells
Thus, you may note that there is a lot of intensive research effort currently involved with the treatment of Diabetes, both Types I and II either to effect a cure or to at least achieve a degree of remission.
