The changes in blood sugar and circulating fats are detected by the pancreas.What is the pancreas?The pancreas is a gland located behind the stomach in the human body. It is both an endocrine gland and an exocrine gland. The exocrine gland secretes digestive enzymes that pass through ducts into the small intestine. The endocrine gland secretes hormones like insulin and glucagon that control blood sugar levels.The pancreas contains specialized cells called islets of Langerhans that detect changes in blood sugar and circulating fats. The cells secrete insulin when blood sugar levels are too high, which causes cells in the body to absorb and store glucose. On the other hand, the cells secrete glucagon when blood sugar levels are too low, which causes cells to release stored glucose into the bloodstream.Circulating fats are detected by the liver. When blood levels of fat are high, the liver converts the excess fat into cholesterol and triglycerides for storage. When blood levels of fat are low, the liver breaks down stored fats and releases them into the bloodstream.