Controlling Blood Glucose Concentration

The pancreas regulates the concentration of glucose in the blood using the hormones insulin and glucagon.

Insulin is a hormone produced in the pancreas that causes cells to take up glucose and stimulates liver and muscle cells to convert glucose to glycogen (a polymer of glucose) for storage.

  • If the concentration of glucose in the blood is too high, cells of the body lose water by osmosis, which damages them

Glucagon is a hormone produced in the pancreas that stimulates liver and muscle cells to break down glycogen into glucose and release it back into the bloodstream.

The diagram below shows this negative feedback cycle and the relationship between insulin and glucagon.

Maintaining blood glucose concentration within an ideal range is an example of homeostasis.

When blood glucose levels are too low:

1. The pancreas releases glucagon into the bloodstream

2. Glucagon stimulates glycogen breakdown in the liver, converting it into glucose

3. This increases the concentration of glucose in the blood back to normal levels

When the blood glucose levels are too high:

1. The pancreas releases insulin into the bloodstream

2. Insulin stimulates the liver to convert glucose into glycogen and it causes cells to take up glucose

3. This decreases the concentration of glucose back to normal levels