Describe and explain the process of insulin secretion

Beta cells store insulin in vesiclesAt normal blood glucose concentration (BGC), K+ channels are open, so K+ can diffuse out of the cell to maintain the potential difference (PD) at -70mVWhen the BGC rises, glucose enters the cells by facilitated diffusion via transporter proteinsThis glucose is phosphorylated in the cell by glucokinase and is used in metabolism to produce ATPK+ channels are ATP sensitive so they close, meaning the PD reduces to -30mV as K+ can no longer diffuse out (more positive ions in the cell)This depolarisation causes voltage-gated Ca2+ channels to openCa2+ diffuses into the cell, triggering the fusion of the vesicles with the cell membraneThe insulin is then secreted out of the cell via exocytosis