text: The glucose that goes into the bloodstream after food consumption also enters the beta cells in the Islets of Langerhans in the pancreas. The glucose diffuses in the beta-cell facilitated by a GLUT-2 vesicle. Inside the beta cell, the following process occurs:
  Glucose gets converted to Glucose-6-Phosphate (G6P) through Glucokinase, and G6P is subsequently oxidized to form ATP. This process inhibits the ATP-sensitive potassium ion channels of the cell causing the Potassium ion channel to close and not function anymore. The closure of the ATP-sensitive potassium channels causes depolarization of the cell membrane causing the cell membrane to stretch which causes the voltage-gated calcium channel on the membrane to open causing an influx of Ca2+ ions.
  This influx then stimulates fusion of the insulin vesicles to the cell membrane and secretion of insulin in the extracellular fluid outside the beta cell; thus making it enter the bloodstream. [Also Illustrated in Figure 1.1.1].
  There are 3 subfamilies of Ca+2 channels; L-type Ca+2 channels, Non-L-Type Ca+2 channels (including R-Type) and the T-type Ca+2 channels. There are two phases of the insulin secretion, the first phase involves the L-type Ca+2 channels and the second phase involves the R-type Ca+2 channels. The Ca+2 influx generated by R-type Ca+2 channels is not enough to cause insulin exocytosis, however, it increases the mobilization of the vesicles towards the cell membrane.