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Insulin

Essay by   •  October 21, 2010  •  3,693 Words (15 Pages)  •  1,098 Views

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Stand on a street corner and ask people if they know what insulin is, and many will reply, "Doesn't it have something to do with blood sugar?" Indeed, that is correct, but such a response is a bit like saying "Mozart? Wasn't he some kind of a musician?" Insulin is a key player in the control of intermediary metabolism. It has profound effects on both carbohydrate and lipid metabolism, and significant influences on protein and mineral metabolism. Consequently, derangements in insulin signaling have widespread and devastating effects on many organs and tissues.

To our surprise, insulin was the first hormone identified (late 1920's) which won the doctor and medical student who discovered it the Nobel Prize (Banting and Best). They discovered insulin by tying a string around the pancreatic duct of several dogs. When they examined the pancreas of these dogs several weeks later, all of the pancreas digestive cells were gone (died and were absorbed by the immune system) and the only thing left was thousands of pancreatic islets. They then isolated the protein from these islets and behold, they discovered insulin. Note that there are other hormones produced by different types of cells within pancreatic islets (glucagon, somatostatin, etc) but insulin is produced in far greater amounts under normal conditions making the simple approach used by Banting and Best quite successful.

Insulin is a hormone. And like many hormones, insulin is a protein. Insulin is secreted by groups of cells within the pancreas called islet cells. The pancreas is an organ that sits behind the stomach and has many functions in addition to insulin production. The pancreas also produces digestive enzymes and other hormones. Carbohydrates (or sugars) are absorbed from the intestines into the bloodstream after a meal. Insulin is then secreted by the pancreas in response to this detected increase in blood sugar. Most cells of the body have insulin receptors which bind the insulin which is in the circulation. When a cell has insulin attached to its surface, the cell activates other receptors designed to absorb glucose (sugar) from the blood stream into the inside of the cell.

Without insulin, you can eat lots of food and actually be in a state of starvation since many of our cells cannot access the calories contained in the glucose very well without the action of insulin. This is why Type 1 diabetics who do not make insulin can become very ill without insulin shots. Insulin is a necessary hormone. Those who develop a deficiency of insulin must have it replaced via shots or pumps (Type 1 Diabetes). More commonly, people will develop insulin resistance (Type 2 Diabetes) rather than a true deficiency of insulin. In this case, the levels of insulin in the blood are similar or even a little higher than in normal, non-diabetic individuals. However, many cells of Type 2 diabetics respond sluggishly to the insulin they make and therefore their cells cannot absorb the sugar molecules well. This leads to blood sugar levels which run higher than normal. Occasionally Type 2 diabetics will need insulin shots but most of the time other methods of treatment will work.

Therefore, the chief feature of diabetes is the lack of insulin. Diabetes is a circumstance in which a break down occurs in the metabolism of the food into power for the human body. It is a serious disorder that effects millions and millions of people each year. Diabetes is one of the oldest diseases known to this date. Since the Ancient days, scientist have made many medical discovers that helps treat diabetes.(Dolger and Seeman 14). Accordingly, diabetes is a chronic, genetically determined, debilitating disease that affects every organ system. There are two major types of diabetes: Type I and Type II. Type I or insulin dependent diabetes mellitus (IDDM), is caused by the autoimmune destruction of the insulin producing cells of the pancreas and is usually, but not always diagnosed in childhood. People with type I diabetes must take insulin shots in order to survive. Type II diabetes or non-insulin dependent diabetes mellitus (NIDDM), are usually diagnosed in adulthood. They produce insulin, but their bodies do not use it effectively or properly. While many modern diseases plague society, diabetes has been known for many centuries (Juvenile Diabetes Foundation, 1-3).

Type I diabetes is usually diagnosed in children and young adults and was previously known as juvenile diabetes. In type I diabetes, the body does not produce insulin. Insulin is necessary for the body to be able to use sugar. Sugar is the basic fuel for the cells in the body, and insulin takes the sugar from the blood into the cells. When sugar builds up in the blood instead of going into cells, it can cause two problems: cells may be starved for energy, and over time, high blood sugar levels may hurt your eyes, kidneys, nerves, or heart. Type 1 Diabetes usually develops due to an autoimmune disorder. This is when the body's immune system behaves inappropriately and starts seeing one of it's own tissues as foreign. In the case of Type 1 Diabetes, the islet cells of the pancreas that produce insulin are seen as the "enemy" by mistake. The body then creates antibodies to fight the "foreign" tissue and destroys the islet cells ability to produce insulin. The lack of sufficient insulin thereby results in diabetes. It is unknown why this autoimmune diabetes develops. Most often it is a genetic tendency. Sometimes it follows a viral infection such as mumps, rubella, cytomegalovirus, measles, influenza, encephalitis, polio or Epstein-Barr virus. Certain people are more genetically prone to this happening although why this occurs is not know. Thus, two people may be infected with the same virus and only one of them who is genetically prone will go on to develop diabetes. Other less common ( very rare) causes of Type 1 Diabetes include injury to the pancreas from toxins, trauma, or after the surgical removal of the majority (or all) of the pancreas.

Type II diabetes is the most common form of diabetes. In type II diabetes, either the body does not produce enough insulin or the cells ignore the insulin. Insulin is necessary for the body to be able to use sugar. Type II diabetes accounts for 90 to 95% of diabetes. Type II diabetes is nearing epidemic proportions, due to an increased number of older Americans, and a greater prevalence of obesity and sedentary lifestyles (Hoffman, 34-49). Diabetes is the leading cause of death. It is the leading cause of kidney failure, adult blindness, and non-traumatic amputations. People who have diabetes are two to four times more likely to have a heart attack or a stroke. Life expectancy of people who have this disease, on the average is fifteen years, less than that of people who do not have the disease.

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