A person who had not eaten for a few hours was given an injection of adrenaline. The person’s blood glucose concentration was measured for 3.5 hours. The graph shows the results.
What is the correct explanation for the change in blood glucose concentration immediately after the injection of adrenaline?
A) Adrenaline causes less glucose to be converted to glucagon.
B) Adrenaline causes less glucagon to be converted to glucose.
C) Adrenaline causes more glucose to be converted to glycogen.
D) Adrenaline causes more glycogen to be converted to glucose.
▶️ Answer/Explanation
Ans: D
Adrenaline triggers the “fight or flight” response, which includes increasing blood glucose levels to provide immediate energy. It does this by stimulating the breakdown of glycogen stored in the liver into glucose (glycogenolysis).
Options A and B are incorrect because glucagon is a hormone, not a product of glucose metabolism. Option C describes glycogenesis (glucose → glycogen), which would lower blood glucose, contrary to the graph’s rise. Thus, D is correct.
When the blood glucose concentration is low, which hormone is released and which organ releases it?
▶️ Answer/Explanation
Ans: A
When blood glucose levels are low, the pancreas releases the hormone glucagon.
Glucagon stimulates the liver to convert stored glycogen into glucose, raising blood sugar levels.
While the liver plays a role in glucose release, it does not produce glucagon. The pancreas (specifically α-cells in the islets of Langerhans) secretes glucagon.
Thus, the correct pairing is glucagon, pancreas (Option A).