Final answer:
Insulin lowers blood glucose levels by promoting glucose uptake, while glucagon raises them by stimulating glycogen breakdown. Together, these hormones operate in a negative feedback loop to maintain blood glucose homeostasis.
Step-by-step explanation:
Insulin and Glucagon in Blood Glucose Regulation
The hormones insulin and glucagon play a critical role in the maintenance of blood glucose levels. Insulin, produced by pancreatic beta cells, lowers blood glucose by stimulating cells to absorb glucose and convert it to glycogen for storage. On the other hand, glucagon, produced by pancreatic alpha cells, raises blood glucose levels by signaling the liver to convert stored glycogen back into glucose. These actions form part of two negative feedback loops, where high blood glucose levels stimulate insulin release to lower blood sugar and low levels trigger glucagon release to increase it.
This system represents a negative feedback loop because the effect of each hormone is to counteract the deviation from normal glucose levels, thus returning the system to its set point. This is opposite to positive feedback loops, where a response enhances the original stimulus. The blood glucose regulation by insulin and glucagon is an essential aspect of homeostasis, ensuring that our body's cells have a steady supply of energy throughout the day.