What is the primary defect in type 2 diabetes mellitus?

What is the primary defect in type 2 diabetes mellitus?

• A. Insulin resistance in muscle, liver, and adipose tissue with beta-cell decline.
• B. Autoimmune destruction of pancreatic beta cells.
• C. Absolute insulin deficiency from birth.
• D. Increased glucagon production only.

Answer: (A)

The primary defect in type 2 diabetes is insulin resistance in muscle, liver, and adipose tissue, with progressive decline of pancreatic beta-cell function. In resistance, the body's cells don’t respond well to insulin, so glucose uptake by muscle and fat is impaired and the liver continues producing glucose even when it shouldn’t. To compensate, the beta cells pump out more insulin, but over time they fatigue and their ability to secrete insulin diminishes. This combination leads to elevated blood glucose and defines type 2 diabetes. Autoimmune destruction of pancreatic beta cells is characteristic of type 1 diabetes, not type 2. Absolute insulin deficiency from birth points to certain genetic or congenital forms of diabetes. Increased glucagon production can contribute to hyperglycemia but is not the primary defect driving type 2 diabetes.

The primary defect in type 2 diabetes is insulin resistance in muscle, liver, and adipose tissue, with progressive decline of pancreatic beta-cell function. In resistance, the body's cells don’t respond well to insulin, so glucose uptake by muscle and fat is impaired and the liver continues producing glucose even when it shouldn’t. To compensate, the beta cells pump out more insulin, but over time they fatigue and their ability to secrete insulin diminishes. This combination leads to elevated blood glucose and defines type 2 diabetes.

Autoimmune destruction of pancreatic beta cells is characteristic of type 1 diabetes, not type 2. Absolute insulin deficiency from birth points to certain genetic or congenital forms of diabetes. Increased glucagon production can contribute to hyperglycemia but is not the primary defect driving type 2 diabetes.