PATHOPHYSIOLOGY OF DIABETES MELLITUS

OBJECTIVES OF THE DISCUSSION:  By the end of this discussion, the learner/Medical student/reader will be able to;

1.  Explain the roles of glucose as a universal fuel for the human body.

2.  Explain the role of insulin in the human body

3.  Explain the alterations in glucose metabolism that later lead to development of diabetes mellitus

INTRODUCTION:  Glucose is the universal fuel molecule for the human body.  For when it is metabolised in cells it generates Adenosine Triphosphate (ATP) and the cell will then be able to run it's activities that require energy.  The entry of glucose into the cells is facilitated by the hormone insulin as we are going to see it in details.  By binding to cell surface receptors, insulin activates entry of glucose molecules into the cells so that they can be utilised for energy production.  This means the human body will require to produce not just enough insulin alone, but also be responsive to it.

In diabetes mellitus, there is impaired uptake of glucose by the cells in the body and glucose will remain in blood circulation, reaching extreme concentrations that are disastrous to the walls of the blood vessels but also, leaving the body cells starving from enough energy source.  In our discussion here, we are going to look at the pathophysiology of this monster disease known as Diabetes Mellitus (DM) but before we continue, let us briefly look at what happen with metabolism of glucose.

METABOLISM OF GLUCOSE:  Glucose also commonly known as blood sugar, is a monomer of polysaccharides, many disaccharides and oligosaccharides, and is a constituent of many carbohydrate food stuffs.  When taken in the body especially in form of food, carbohydrates yield this precious source of fuel in the body as part of digestion in the gastrointestinal tract.  Digestion of carbohydrates

The glucose produced as a result of food breakdown in the Gastro-intestinal Tract (GIT) is then absorbed into the lumen of the intestines, to blood circulation and in the next few minutes following a heavy meal, the glucose levels in blood will be higher than normal.  The excess of it will then be converted to glycogen and stored for later use in the liver and skeletal muscles, and the rest of it will remain in circulation ready to be taken up by cells.  The liver carries out the role of converting this extra glucose into glycogen for later use, and the rest of glucose is absorbed into the cells to provide energy.  For glucose to enter the cells, the goal is accomplished by the endocrine system via a hormone known as insulin, produced by the endocrine pancreas.

DEVELPMENT OF DIABETES MELLITUS: Development of diabetes follows the body's inability to absorb glucose from the blood circulation either as a result of insufficient production of insulin from the pancreas, cellular resistance to circulating insulin or both and therefore increasing load of glucose in circulation.

TYPES OF DIABETS:  Now that we have seen the issue is insulin and glucose, there are two aspects; The insulin produced in the pancreas is not enough or it is not produced at all, and this will be termed Diabetes mellitus type 1 or Insulin dependent diabetes mellitus.

The other aspect will be, the pancreas is normal and producing enough insulin but the body cells are not sensitive to the produced insulin and therefore the produced insulin noes not work despite it's presence.  This is termed Diabetes mellitus type 2 or Non Insulin dependent diabetes mellitus.

SUMMERY:  That describes the out goings of glucose metabolism, insulin production, and development of diabetes.  To read about the detailed description for the types of diabetes, possible causes of pancreatic failure and management of diabetes click here.

RELATED;

1.  POLYSACCHARIDES

2.  DISACCHARIDES

3.  CARBOHYDRATES

4.  DIGESTION OF CARBOHYDRATES

5.  THE ENDOCRINE PANCREAS

6.  MEDICAL MANAGEMENT OF DIABETES MELLITUS

7.  PANCREATITIS