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.Nerve, muscle, and certain other cell types such as the islet cells of the pancreas of vertebrates exhibit a special property called electrical excitability.As the action potential passes the recording electrode, the voltmeter or oscilloscope will display a characteristic pattern of membrane potential changes.An electrode called the stimulating electrode is connected to a power source and inserted into the axon some distance from the recording electrode (see Figure 13-3b).Alan Hodgkin and Andrew Huxley used micro electrodes and the squid giant axon to learn how action potentials are generated; for their work, they received a share of the Nobel Prize in 1963.A brief impulse from this stimulating electrode depolarizes the membrane by about 20 mV (i.e., from -60 to about -40 mV), bringing the neuron beyond the threshold potential.To understand how nerve cells use action potentials to transmit signals, we must first examine how cells generate a resting membrane potential and how the membrane potential changes during an action potential.This triggers an action potential that propagates away from the stimulating electrode.

.Nerve, muscle, and certain other cell types such as the
islet cells of the pancreas of vertebrates exhibit a special
property called electrical excitability. In electrically
excitable cells, certain types of stimuli trigger a rapid
sequence of changes in membrane potential known as an
action potential. During an action potential, the membrane potential changes from negative to positive values
and then back to negative values again, all in as little as a few milliseconds. In addition to measuring resting potential, microelectrodes can also be used to measure these
dynamic changes in membrane potential. An electrode
called the stimulating electrode is connected to a power
source and inserted into the axon some distance from the recording electrode (see Figure 13-3b). A brief impulse
from this stimulating electrode depolarizes the membrane
by about 20 mV (i.e., from -60 to about -40 mV), bringing the neuron beyond the threshold potential. This
triggers an action potential that propagates away from the
stimulating electrode. As the action potential passes the recording electrode, the voltmeter or oscilloscope will
display a characteristic pattern of membrane potential
changes. Alan Hodgkin and Andrew Huxley used micro electrodes and the squid giant axon to learn how action
potentials are generated; for their work, they received a
share of the Nobel Prize in 1963. To understand how
nerve cells use action potentials to transmit signals, we
must first examine how cells generate a resting membrane
potential and how the membrane potential changes during an action potential.