The pancreas is located behind the stomach in the curve of the duodenum. The pancreas may be considered both an endocrine and an exocrine gland since pancreatic juices are secreted through the common pancreatic duct. Two types of tissue make up the pancreas. The acini secrete digestive juices into the duodenum. The Islets of Langerhans is the endocrine tissue. The Islets of Langerhans contains two types of cells, each type produces a particular hormone. Alpha cells produce glucagon. Beta cells produce insulin, a hormone essential to the body's metabolism.
a. Glucagon. Glucagon is frequently called the hyperglycemic factor. Glucagon causes glycogenolysis (the conversion of glycogen into glucose) and tends to prevent hypoglycemia. Glucagon is released when blood glucose levels drop, thus, glucagon tends to raise the level of sugar in the blood.
b. Insulin. Insulin's principal effect is to increase the cells' permeability to glucose. When the glucose enters the cells, it is metabolized to produce energy. Insulin also increases glycogenesis in the liver, thus, it increases glycogen stored there. A hyposecretion of insulin is known as diabetes mellitus. There are essentially two types of diabetes, juvenile diabetes and maturity-onset diabetes. Juvenile diabetes develops early in life, usually about the time of puberty, and is frequently associated with ketoacidosis. This form of diabetes is treated with insulin therapy. Maturity-onset diabetes frequently does not appear until middle age. Maturity-onset diabetes is usually milder than juvenile diabetes. Furthermore, maturity-onset diabetes is sometimes managed by the administrating of oral hypoglycemics and by controlling the patient's weight and diet. The lack of insulin decreases the amount of glucose that enters the cells of the body and increases the amount of glucose present in the person's blood (hyperglycemia). Hyperglycemia causes sugar to spill over into the urine. This results in glycosuria and polyuria (due to the osmotic effect of the glucose). The lack of glucose entering the cells causes gluconeogenesis and fat catabolism. This result in wasting of the cells and ketoacidosis. Ketoacidosis leads to coma and death. Uncontrolled diabetes mellitus may be accompanied by hyperglycemia, glycosuria, polyuria, polydipsia (excessive thirst leading to increased water intake), ketoacidosis, wasting coma, and death. A person who has diabetes mellitus may be required to take insulin to treat the lack of insulin present in the body. If a person must take insulin, it is likely that this individual must take insulin for the remainder of his or her life. Remember, insulin taken by the diabetic does not cure diabetes. In the opposite fashion, an overdose of insulin may cause hypoglycemia, depression of the central nervous system, and death. One possible treatment of this condition is an injection of glucagon. Remember, when injected, glucagon causes glycogenesis that results in an elevated level of blood sugar.
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