Adrenaline triggers glycogenolysis to raise low blood glucose

Steps:

• Adrenaline is secreted during stress when blood glucose falls below its set point (around 5 mM).
• It binds to liver receptors, activating glycogen phosphorylase to break down glycogen into glucose-1-phosphate.
• This releases glucose into blood, reducing liver glycogen concentration on the graph.
• The period showing rapid glycogen decrease indicates adrenaline's corrective action.

Why B is correct:

• Period B shows decreasing glycogen, matching adrenaline's role in glycogenolysis per the fight-or-flight response.

Why the others are wrong:

• A: Glycogen stable or increasing, indicating no breakdown (e.g., fed state with insulin dominance).
• C: Glycogen at minimum or recovering, post-adrenaline without active secretion.
• D: Glycogen steady or irrelevant to low glucose correction.

Final answer: B