Insulin is a hormone that is produced by beta cells in the Islets of Langerhans in the pancreas. A hormone is a chemical substance that is transported in the blood and stimulates particular cells to perform a function. The homeostasis (maintaining of a substance within normal limits in the body) of glucose is very important to every aspect of the body as glucose is needed for respiration to produce ATP, which is the energy currency of a cell. Therefore, it is carefully regulated by a balance between insulin and glucagon. When the concentration of glucose in the blood gets too high; the beta cells start to release insulin into the blood, this travels to all the cells in the body. Insulin works in 3 ways to decrease the concentration of glucose in the blood:Increasing the uptake of glucose into cells (by incorporating a glucose transporter into the cell membrane)Increasing the rate of respiration, so more glucose is being used Turning glucose in glycogen in the liver, glycogen is the the main storage molecule in the body so this means there is a store of glucose for later if the concentration dips too low. Any questions?