The differences in ion
distribution across a membrane results in a voltage difference (or
potential) across the membranes of all cells.
The sodium/potassium pumps and
the differential permeabilities of ion channels in the membrane
create a concentration of sodium ions that is higher on the outside
of the membrane and a concentration of potassium ions that is higher
on the inside of the membrane.
Some signals can produce ion
flow changes in a neuron. In this Lesson, youll learn about a
unique feature of neurons, called the action potential, that results
from ion flow changes.
Action potentials cause the
release of chemical messengers from the neurons. Nerve gases and
many drugs interfere with these chemical messengers.