5.3.2 - Control of Blood Glucose Concentration

Which organ monitors and controls blood glucose concentration?

The pancreas

How does the pancreas respond when blood glucose levels are too high?

The pancreas secretes the hormone insulin. Insulin binds to receptors on the liver and muscles, causing excess glucose to be converted into glycogen and stored.

How does the pancreas respond when blood glucose levels are too low?

The pancreas secretes the hormone glucagon. Glucagon binds to liver cells, causing glycogen to be converted into glucose and released into the blood.

How is blood glucose concentration controlled using a negative feedback loop?

• When the blood glucose concentration rises or falls below the optimum, a hormone is secreted by the pancreas.

• The action of either hormone (insulin or glucagon) helps bring back the concentration to the correct level.

What is Type 1 diabetes?

• An autoimmune disorder in which the pancreas doesn’t produce sufficient insulin to control the blood glucose concentration.

• As a result, blood glucose levels are often very high, leading to excessive urination, tiredness and weight loss.

How can Type 1 diabetes be treated?

• Insulin injections before meals - allows glucose to be converted into glycogen.

• Limiting carbohydrate intake.

• Attempts using pancreas and pancreatic cell transplants; investigations into genetic engineering of pancreatic cells.

What is Type 2 diabetes?

• A disorder in which the body’s cells stop responding to insulin, leading to an uncontrolled blood glucose concentration.

• Its onset is linked with increasing age and obesity.

How can Type 2 diabetes be treated?

• Following a carefully-controlled diet.

• Doing regular exercise.

• Losing weight.

• Use of drugs which increase insulin production and effectiveness.