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According to McCance and Huether (2019), 9.3 % of the adult population in the United States is affected by Type 2 diabetes mellitus. Risk factors for developing Type 2 diabetes are family history, hypertension, obesity, and increased age. Lifestyle choices, genetic factors, and environmental factors combined can all contribute to the development of Type 2 diabetes mellitus. One main issue leading to Type 2 diabetes is insulin resistance in peripheral tissues specifically the muscle, liver, and adipose tissue (McCance & Huether, 2019).
Alpha cells and beta cells are islet cells that are found in the pancreas. The beta cells are responsible for creating insulin and the alpha cells are responsible for creating glucagon. The increasingly high glucagon levels cause blood glucose levels to increase leading to the stimulation of gluconeogenesis and glycogenolysis (McCance & Huether, 2019). Due to the decreased reactiveness of the alpha cells to glucose, the glucagon secretion begins increasing as well. Amylin which is a beta-cell hormone is responsible for repressing the alpha cells release of glucagon (McCance & Huether, 2019). In Type 2 diabetes the cells begin to become insulin resistant. This means the needed glucose is unable to get inside of the cells which causes it to accumulate in the blood. In this case, the insulin receptors are abnormal or missing causing glucose to be locked out of the cells.
The beta cells attempt to keep up with the increased demand for insulin but eventually lose the ability to produce enough. The beta cells begin to decrease in number and size and eventually fail due to exhaustion (McCance & Huether, 2019). This leads to hyperglycemia which is the buildup of glucose in the bloodstream. In an attempt to compensate for hyperglycemia, the pancreas will produce more insulin. The pancreas will eventually reach exhaustion and no longer be able to compete with the body’s increased demand for insulin.
Our GI hormones (gut hormones) contribute to diabetes & insulin resistance as well. Ghrelin is a hormone made in the stomach and pancreatic islets that control food intake. Insulin resistance has been associated with reduced levels of ghrelin. Incretins are released from the GI tract to increase insulin release, regenerate the beta-cell and provide a barrier to beta-cell damage (McCance & Huether, 2019). Studies show the incretin glucagon-like peptide 1, (GLP-1) depicts a decrease in beta-cell responsiveness in type 2 diabetes (McCance & Huether, 2019).
Due to hyperglycemia and the current lack of insulin polyphagia, polydipsia and polyuria are classic signs that appear while recurrent infections and visual changes occur later on. If hyperglycemia continues to progress without treatment microvascular complications such as nephropathy, neuropathy, and retinopathy can occur along with macrovascular complications: cerebrovascular disease, coronary artery disease, and peripheral artery disease (McCance & Huether, 2019).
According to the American Diabetes Association (2015), there are four ways to diagnose Type 2 diabetes
- Glycated hemoglobin (A1C) test: Diabetics diagnosed using this test will have an A1C of 6.5% or higher
- Random blood sugar test: Diabetics diagnosed using this test will have a blood sugar of > 200 mg/dL
- Fasting plasma glucose (FPG): Diabetics diagnosed using this test will have a FPG of 126 mg/dL or higher
- Oral glucose tolerance test (OGTT): Diabetics diagnosed using this test will have an OGTT of 200 mg/dL or higher.
References
American Diabetes Association. (2015, January 1). 2. Classification and Diagnosis of Diabetes. Retrieved from https://care.diabetesjournals.org/content/38/Supplement_1/S8.
McCance, K. L., Huether, S. E., Brashers, V. L., & Rote, N. S. (2019). Pathophysiology: the biologic basis for disease in adults and children (8th ed.). St. Louis, MO: Elsevier.