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How Insulin works?

Whatch this video -----good demonstration  ----

http://www.youtube.com/watch?v=CuQMpN7rM-4

Wikipedia  --- Insulin
Reference -----

                            Insulin is a peptide hormone, produced by beta cells of the pancreas, and is central to regulating carbohydrate and fat metabolism in the body. Insulin causes cells in the liver, skeletal muscles, and fat tissue to take up glucose from the blood. In the liver and skeletal muscles, glucose is stored as glycogen, and in adipocytes it is stored as triglycerides.

                          Insulin stops the use of fat as an energy source by inhibiting the release of glucagon. With the exception of the metabolic disorder diabetes mellitus and metabolic syndrome, insulin is provided within the body in a constant proportion to remove excess glucose from the blood, which otherwise would be toxic. When blood glucose levels fall below a certain level, the body begins to use stored sugar as an energy source through glycogenolysis, which breaks down the glycogen stored in the liver and muscles into glucose, which can then be utilized as an energy source. As a central metabolic control mechanism, its status is also used as a control signal to other body systems (such as amino acid uptake by body cells). In addition, it has several other anabolic effects throughout the body.

                       When control of insulin levels fails, diabetes mellitus can result. As a consequence, insulin is used medically to treat some forms of diabetes mellitus. Patients with type 1 diabetes depend on external insulin (most commonly injected subcutaneously) for their survival because the hormone is no longer produced internally.[2] Patients with type 2 diabetes are often insulin resistant and, because of such resistance, may suffer from a "relative" insulin deficiency. Some patients with type 2 diabetes may eventually require insulin if other medications fail to control blood glucose levels adequately. Over 40% of those with Type 2 diabetes require insulin as part of their diabetes management plan.
The human insulin protein is composed of 51 amino acids, and has a molecular weight of 5808 Da. It is a dimer of an A-chain and a B-chain, which are linked together by disulfide bonds.

                      Insulin's name is derived from the Latin insula for "island". Insulin's structure varies slightly between species of animals. Insulin from animal sources differs somewhat in "strength" (in carbohydrate metabolism control effects) in humans because of those variations. Porcine insulin is especially close to the human version.


How do glucagon and insulin work together?

                               Insulin is secreted when blood sugar rises. It works by stimulating receptors on tissue cells to escort glucose into the cells. It all suppresses glucagon, hormone-sensitive lipase (a hormone responsible for mobilizing and using fat stores) and suppresses the appetite centers in the brain. 

                                   Glucagon is secreted when blood sugar is low. It triggers gluconeogenesis in the liver, which means that fats and proteins are converted into glucose and released into the blood. It also is responsible for mobilizing glycogen stores, suppresses insulin, and mobilizes fat stores. So glucagon and insulin not only do opposite things, they are antagonistic to each other, meaning when one is high the other one is low. They do not technically work "together". 

                                 High levels of insulin are common in those who consume excessive calories and excessive carbohydrate foods. For those who are sensitive to the effects of insulin, this can cause reactive hypoglycemia and obesity.





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