Which organ is primarily responsible for regulating glucose levels in the blood?

The organ primarily responsible for regulating glucose levels in the blood is the pancreas. The pancreas plays a critical role in glucose homeostasis through the secretion of hormones, particularly insulin and glucagon.

When blood glucose levels rise, such as after a meal, the pancreas releases insulin, which facilitates the uptake of glucose by cells and encourages the liver to convert excess glucose into glycogen for storage. Conversely, when blood glucose levels drop, the pancreas releases glucagon, which stimulates the liver to convert glycogen back into glucose and release it into the bloodstream.

While the liver is indeed involved in glucose metabolism, it acts in response to the hormones secreted by the pancreas rather than independently regulating glucose levels. Therefore, understanding the interactive roles of these organs highlights the pancreas as the key regulatory gland in blood glucose levels. The spleen and stomach do not have direct roles in this regulation, further emphasizing the distinct function of the pancreas in maintaining glucose homeostasis.