What characterizes the pathophysiology of type 2 diabetes mellitus?

• A. Insulin resistance in skeletal muscle, liver, and adipose tissue, with a decline in pancreatic beta-cell function.
• B. Autoimmune destruction of pancreatic beta cells.
• C. Absolute insulin deficiency present from birth.
• D. Excess insulin production by beta cells.

Answer: (A)

Insulin resistance in skeletal muscle, liver, and adipose tissue, with progressive decline in pancreatic beta-cell function. In type 2 diabetes, tissues respond poorly to insulin, so glucose uptake is impaired and hepatic glucose production remains inappropriately high. To compensate, beta cells increase insulin secretion, but over time their capacity wanes and relative insulin deficiency develops. This combination drives hyperglycemia and the characteristic metabolic disturbances. By contrast, autoimmune destruction of beta cells describes type 1 diabetes, absolute insulin deficiency present from birth or early life points to other forms, and excess insulin production is not typical of type 2 ( though early insulin levels may be elevated as a compensatory response).