controlling blood glucose

• It is essential that your cells have a constant supply of the glucose they need for respiration. To achieve this, one of your body systems responds to changes in your blood glucose levels and controls it to within very narrow limits. 

  This is an example of homeostasis in action.
• • When you digest a meal, large amounts of glucose pass into your blood.
• Without a control mechanism, your blood glucose levels would vary significantly. They would range from very high after a meal to very low several hours later - so low that cells would not have enough glucose to respire. This situation is prevented by your pancreas.
• • The pancreas is a small pink organ found under your stomach. 
  • It constantly monitors and controls your blood glucose concentration using two hormones: insulin and glucagon
• When your blood glucose concentration rises after you have eaten a meal, the pancreas produces insulin. 
• Insulin allows glucose to move from the blood into your cells where it is used.
• Soluble glucose is also converted to an insoluble carbohydrate called glycogen.
• Insulin controls the storage of glycogen in your liver and muscles.
• • Stored glycogen can be converted back into glucose when it is needed. 
  • As a result, your blood glucose stays stable within a narrow concentration range.
• When your blood glucose concentration falls below the ideal range, the pancreas secretes another hormone called glucagon. 
• Glucagon makes your liver break down glycogen, converting it back into glucose. In this way, the stored glucose is released back into the blood.
• By using two hormones and the glycogen store in your liver, your pancreas keeps your blood glucose concentration fairly constant
• It does this using negative feedback control, which involves switching between the two hormones
• In type 1 diabetes, your pancreas does not make enough (or any) insulin, and your blood glucose is not controlled
• Without insulin your blood glucose levels get very high, glucose cannot get into the cells of your body, so you lack energy and feel tired, it can even cause death.
• Type 1 diabetes is a disorder that usually starts in young children and teenagers. There seems to be a genetic element to the development of the disease.
• Type 1 diabetes is normally controlled by injecting insulin to replace the hormone that is not made in the body
• In type 2 diabetes, the pancreas still makes insulin, but your body stops responding to it
• It gets more common as people get older and is often linked to obesity, lack of exercise, or both
• In countries such as the UK and the USA, levels of type 2 diabetes are rising rapidly as obesity becomes more common.
• Type 2 diabetes is often treated by a carbohydrate-controlled diet and taking more exercise. If this doesn't work, drugs may be needed.