Final answer:
CHO metabolism maintains blood glucose levels within 70 to 110 mg/dL, with glucagon raising low levels by converting glycogen to glucose, in a negative feedback loop that involves insulin decreasing high blood sugar levels.
Step-by-step explanation:
A primary purpose of CHO (carbohydrate) metabolism is to help maintain blood glucose levels between the normal physiological limits of approximately 70 to 110 mg/dL. This regulation is critically important for bodily functions because glucose is the primary fuel for cells, especially the brain. The hormone glucagon plays a critical role in this homeostasis, particularly when blood glucose levels are low. Alpha cells in the pancreas produce glucagon, which stimulates the conversion of stored glycogen in the liver back into glucose, thereby increasing blood glucose levels. This mechanism is part of a negative feedback loop designed to return blood glucose levels to a safe range.
Insulin and glucagon are the two hormones mainly responsible for maintaining this balance. Insulin is released by the beta cells of the pancreas to lower blood glucose levels, promoting glucose uptake and its storage as glycogen in muscle and liver cells. Conversely, as blood glucose levels begin to drop, glucagon is secreted to raise these levels to ensure a continuous supply of energy to all cells, particularly the brain, which relies exclusively on glucose for energy.