The role of insulin is to:

• A. Increase glucose production
• B. Decrease urine production
• C. Lower blood glucose by promoting cellular uptake
• D. Slows digestion

Answer: (C)

Insulin lowers blood glucose by promoting cellular uptake of glucose. When blood sugar rises after eating, the pancreas releases insulin. Insulin binds to receptors on muscle and adipose tissue, triggering GLUT4 transporters to move to the cell surface so glucose can move from the blood into cells to be used for energy or stored. In the liver, insulin promotes conversion of glucose to glycogen and suppresses new glucose production, helping to further reduce blood glucose levels.

The other ideas don’t reflect insulin’s main action: it does not directly increase glucose production, it doesn’t directly increase urine output, and it does not slow digestion.