Chapter I Introduction to Diabetes Mellitus
Insulin is a hormone produced by the pancreas. The pancreas either produces no insulin, too little insulin, or the body does not respond to the insulin produced. This causes a build-up of glucose in the blood, creating high glucose levels in the body since the body is unable to utilize the glucose for energy. This high concentration of glucose in the blood is called hyperglycemia. During the normal digestive process, the body converts food into glucose to be used by the body’s cells as an energy source. Foods eaten are made of carbohydrates, proteins, and fats. These foods are broken down to provide fuel for the cells, which are converted into glucose, a simple sugar. Glucose enters the cells through receptor sites that accept insulin, which facilitates the passage of glucose to the cell. Excess glucose is stored in the liver and muscles in the form of glycogen. When the body is low on fuel and the blood sugar is low, glycogen, stored in the liver, is released to form glucose. The liver is also able to make new sugar, which it gets from protein taken from the muscles. Beta cells regulate blood glucose levels constantly and deliver the required amounts of insulin needed to transfer glucose into the cells. This process keeps glucose levels in the normal range of 60 – 120mg/ml. Glucose has difficulty entering the cells when there is little or no insulin in the body, or when there is an inappropriate response to the insulin produced. When blood glucose rises above 180mg/ml, or what is termed the kidney threshold, it is removed from the body in the urine. This is called glycosuria. Often, people with long-term diabetes or kidney disease develop a high kidney threshold, which means that glucose does not spill over into the urine until the blood sugar is extremely high. The regulation of glucose is closely regulated in normal individuals. In healthy people, the secretion of insulin and the amount of glucose are closely coordinated. The amount of glucose released by the liver is directly proportionate to the amount of glucose used by the tissues. Therefore, if glucose concentration decreases, insulin concentration deceases, and if glucose concentrations increase, so does the need for insulin. In the diabetic, the renal tubules are unable to absorb all of the glucose filtered by the glomeruli. The renal excretion of glucose requires excretion of water and produces an osmotic dieresis. This dieresis is called polyuria or excessive urination. Polyuria can cause dehydration, resulting in dry skin and blurred vision, which is due to fluctuation in the amount of glucose and water in the lenses of the eye during dehydration. Glucose needs water to flow from the body. Loss of water causes an increase in the serum polarity that stimulates the thirst center in the hypothalamus. This results in a condition called polydipsia, or excessive thirst. Symptoms may range from pronounced to nothing more than a dry mouth. Polyhagia, or excessive hunger, is caused by the body’s inability to transfer, via insulin, glucose through the receptors into the cells. Without glucose as fuel, the cells starve. Since the cells cannot produce energy, the diabetic patient feels weak and tired. The glucose needed for fuel is being lost through the urine. Weight loss occurs in people that produce no insulin because fuel does not enter the cells. When insulin is low, the body breaks down as fuel, and rapid weight loss occurs. As far cells breakdown, fatty acids are formed. These fatty acids pass through the liver to form ketones. Ketones are excreted in the urine. This is called kentonuria. FACTORS THAT INCREASE THE RISK OF DIABETES Heredity: There is approximately a 5% risk of developing diabetes if your mother, father, or sibling has diabetes. The risk increases to almost 50% of reported cases, if parents or siblings have diabetes and are overweight. Obesity: 80% of people with Type 2 diabetes are overweight, with symptoms disappearing with weight loss. Age: Fewer beta calls produce insulin with age. Viruses: Certain viruses may destroy beta cells Faulty Immune System: Multiple factors may cause the immune system to destroy beta cells, such as infection. Physical Trauma: Injury or trauma may destroy the ability of the pancreas to produce insulin. Drugs Drugs used for other conditions could cause the development of diabetes. Stress Hormones at times of stress may block the effectiveness of insulin. Pregnancy Hormones produced during pregnancy can block the effectiveness of insulin. |