(Original post by ds4143)
Ohh I dont think thats right because k ions moves out just like at resting potential of a neurone, if you remember that? And i wasnt too sure about the Na and K channels, but I just checked the book now page 26, its does only say that the b-cells has Ca and K ion channels.
From your point 4 onwards is correct..
So just to make sure..
1) b-cells has Ca and K ion channels. K ions move out of the cell causing a potential difference of -70mV
2) when glucose in the blood increase, it moves into the cell via diffusion.
3) glucose is quickly respired, producing ATP, an increase in ATP causes k channels to shut. Cell becomes less negative.
4) depolarisation causes Ca channels to open, Ca enters, vesicles containing insulin, fuses and releases i.sulin by exocytosis
There you go
you were close
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