AAMC FL Practice Exam

What is the role of glucagon in the body?

1. Decreases blood sugar levels

2. Increases blood sugar levels

3. Stimulates protein synthesis

4. Enhances iron absorption

The correct answer is: Increases blood sugar levels

Glucagon plays a critical role in regulating blood glucose levels in the body, primarily by increasing blood sugar levels. It is a hormone produced by the alpha cells of the pancreas, and its main function is to prompt the liver to release stored glucose into the bloodstream. This process occurs during periods of low blood sugar, such as between meals or during fasting. When blood sugar levels drop, glucagon is released, leading to two primary effects in the liver. First, it stimulates glycogenolysis, which is the breakdown of glycogen into glucose. Second, it promotes gluconeogenesis, the process of synthesizing new glucose from non-carbohydrate sources. These actions help to raise blood glucose levels, ensuring that the body has a steady supply of energy available to cells, particularly important for vital organs like the brain. Understanding the function of glucagon highlights its role in maintaining glucose homeostasis, distinct from insulin, which decreases blood sugar levels by facilitating the uptake of glucose into cells and promoting storage. Therefore, the option indicating that glucagon increases blood sugar levels accurately reflects its physiological role in the body.