How does the body respond to low blood sugar levels?

The body responds to low blood sugar levels by secreting glucagon. Glucagon is a hormone produced by the alpha cells of the pancreas. When blood glucose levels drop, glucagon is released into the bloodstream to help raise these levels back to normal.

Specifically, glucagon acts primarily on the liver, stimulating the conversion of glycogen to glucose in a process known as glycogenolysis. It also promotes gluconeogenesis, which is the generation of glucose from non-carbohydrate sources. This action is critical for maintaining adequate levels of glucose in the blood, especially between meals or during periods of fasting.

While cortisol could also play a role in regulating blood sugar levels during prolonged fasting or stress, glucagon is the primary hormone responsible for the immediate response to low blood sugar. Other hormones like insulin would not be released during hypoglycemia as their function is to lower blood sugar levels, not raise them. Additionally, increasing metabolic rate is more related to energy expenditure rather than an immediate response to blood sugar levels. Thus, the secretion of glucagon is the key physiological response to counteract low blood sugar levels effectively.