Maintaining Blood Glucose Levels (WJEC GCSE Biology)

Blood Glucose Levels

• Blood glucose concentration is monitored and controlled by the pancreas

• The pancreas is an endocrine gland (making and secreting hormones into the bloodstream) 

• Blood glucose concentration must be kept within a narrow range, so it’s an example of homeostasis 

  • Too high a level of glucose in the blood can lead to cells of the body losing water by osmosis, which can be dangerous

  • Too low a level of glucose in the blood can lead to the brain receiving insufficient glucose for respiration, potentially leading to a coma or even death

• If the blood glucose concentration gets too high:

  • Cells in the pancreas detect the increased blood glucose levels

  • The pancreas produces the hormone insulin, secreting it into the blood

  • Insulin stimulates muscles and the liver to take up glucose from the bloodstream and store it as glycogen (an insoluble polymer of glucose)

  • This reduces the concentration of glucose in the blood back to normal levels, at which point the pancreas stops secreting insulin

Control of blood glucose diagram

The hormone insulin regulates the blood glucose levels when they become too high