Insulin and glucagon operate as a negative feedback system to keep blood glucose within a narrow, stable range.

The pancreas contains both beta cells, which produce insulin, and alpha cells, which produce glucagon. When blood sugar rises, beta cells secrete insulin to lower it. When blood sugar drops, alpha cells release glucagon to raise it. This opposing push-pull creates a self-correcting loop. The system adjusts constantly, ensuring cells receive a steady fuel supply without dangerous spikes or crashes.