Insulin Release: Insulin Release:
+
The K channels into a beta cell are
normally open & the Ca+ channels are
normally closed.
K+ ions diffuse out of the cell causing
the inside to become more negative
than the outside.
As glucose concentration outside the
cells increase, glucose moves into the
cell via diffusion.
Under the influence of the enzyme
glucokinase, glucose is metabolised to
produce ATP.
The generation of extra ATP causes
the K+ channels to close.
The K+ now remain in the cell, causing
the inside of the cell to become less
negative.
The insulin is packaged into vesicles &
these move towards the plasma
membrane.
The vesicles fuse with the plasma
membrane & release insulin via
exocytosis.
The insulin travels in the blood to the
target cells.
+
The K channels into a beta cell are
normally open & the Ca+ channels are
normally closed.
K+ ions diffuse out of the cell causing
the inside to become more negative
than the outside.
As glucose concentration outside the
cells increase, glucose moves into the
cell via diffusion.
Under the influence of the enzyme
glucokinase, glucose is metabolised to
produce ATP.
The generation of extra ATP causes
the K+ channels to close.
The K+ now remain in the cell, causing
the inside of the cell to become less
negative.
The insulin is packaged into vesicles &
these move towards the plasma
membrane.
The vesicles fuse with the plasma
membrane & release insulin via
exocytosis.
The insulin travels in the blood to the
target cells.
