Controlling Blood Glucose

• Eating foods containing carbohydrates puts glucose into the blood from the gut
• The normal metabolism of cells removes glucose from the blood
• Vigorous exercise removes much more glucose from the blood than the normal metabolism of cells
• Excess glucose can be stored as glycogen in the liver and in the muscles
• The level of glucose in the blood must be kept steady
• Changes in the blood-glucose level are monitored and controlled by the pancreas, using the hormones insulin and glucagon, in a negative feedback cycle
• Blood-glucose level is too high:

  • insulin is secreted by the pancreas into the blood
  • insulin makes the liver turn glucose into glycogen
  • glucose moves from the blood into the liver and muscle cells
  • the blood-glucose level is reduced
• Blood-glucose level is too low:

  • glucagon is secreted by the pancreas into the blood
  • glucagon makes the liver turn glycogen into glucose
  • glucose is released into the blood by the liver
  • the blood-glucose level is increased