[Campbell Biology P.965] According to the provided information and diagram, what primary mec... | Practice Question

According to the provided information and diagram, what primary mechanism is activated when blood glucose levels drop below the normal range e.g., after fasting ?

  • A: Beta cells of the pancreas secrete insulin, enhancing the transport of glucose into body cells.
  • B: Alpha cells of the pancreas secrete glucagon, stimulating the liver to break down glycogen and release glucose into the blood.
  • C: The pancreas produces and secretes bicarbonate ions and digestive enzymes into the small intestine.
  • D: Brain cells increase their independent uptake of glucose from the blood, reducing overall blood glucose.

Explanation

When blood glucose levels drop, alpha cells of the pancreas release glucagon. Glucagon acts primarily on the liver, stimulating the breakdown of glycogen glycogenolysis and the conversion of non-carbohydrate sources into glucose gluconeogenesis , releasing glucose into the blood to raise its concentration back to the normal range.