by a wave-like exchange of sodium and potassium ions
but the signal doesn’t travel through the
core;
it travels along the surface membrane.
Squid giant axon
The bigger the axon
the faster it works.
The axon of Atlantic squid,
controlling its water-jet propulsion,
evolved to increase
its chance of escaping predators.
Reactions
Knee-jerk reactions
save effort.
At least imitate
people you look up to.
Sports and war
breed snap decisions,
but violence
is a poor long-term plan.
Standing on dry land
you might seem as dumb as a fish.
The context
makes the difference.
Positive-charged sodium ions from outside of the cell membrane
exchange positions with negative-charged potassium ions from
inside. This exchange propagates in a fraction of a millisecond
from the neuron to the axon terminal. Hodgkin and Huxley managed
to measure this extremely fast event using voltage clamps on the
giant axon of squid.
Later, Andrew Huxley was the first to describe how muscles
contract.
Positive-charged sodium ions from outside of the cell membrane exchange positions with negative-charged potassium ions from inside. This exchange propagates in a fraction of a millisecond from the neuron to the axon terminal. Hodgkin and Huxley managed to measure this extremely fast event using voltage clamps on the giant axon of squid. Later, Andrew Huxley was the first to describe how muscles contract.
See also in The book of science:
Readings on wikipedia: