The concentration of glucose in your blood needs to be kept within a certain limit because glucose is needed by cells for respiration. It is controlled by the pancreas.

Rigorous activity, e.g. exercise, uses glucose for respiration and therefore there is less in the blood.

• If glucose levels decrease, the pancreas produces the hormone glucagon
• Glucagon binds to to the liver cells causing glycogen to be broken down into glucose
• Glucose is released into the blood, increasing the blood glucose concentration

Type 1 diabetes: The pancreas cannot produce enough insulin.

• Blood glucose level can rise to a fatal amount
• Glucose is excreted with urine and lots of urine is produced leaving the individual very thirsty
• It is treated with insulin injections at meal times, which results in glucose being taken up from the bloodstream
• It is also advised to limit the intake of simple carbohydrates which contain lots of glucose
• Doctors are attempting to cure diabetes with pancreas and pancreatic cell transplants, and genetically engineering pancreatic cells from mice to make insulin

Type 2 diabetes The body cells no longer respond to insulin.

• Blood glucose levels can rise to a fatal amount
• Obesity is a risk factor for this disease
• Treatments include reducing the number of simple carbohydrates in diet, losing weight and increasing exercise
• There are also drugs to make insulin more effective on body cells, help the pancreas make more insulin or reduce the amount of glucose absorbed from the gut