Final answer:
The brain is responsible for regulating hunger and satiety signals, with the help of leptin from fat cells and satiety signals from the gastrointestinal tract; the pancreas does contribute through glucose regulation.
Step-by-step explanation:
The brain is the central organ that regulates hunger and satiety signals through various mechanisms. When blood glucose levels rise, the pancreas and the liver aid in signaling the brain to stop eating. Additionally, the gastrointestinal tract provides satiety signals to the brain as food passes through it. Moreover, fat cells release leptin, a hormone that signals satiety. Although the pancreas does play a role in these processes, particularly in blood glucose regulation, the direct control of hunger and satiety is generally attributed to the brain's function rather than the release of hormones from the pancreas or other digestive organs mentioned.