|How fast can neurons transmit through your body
for the nervous system to function? Thanks|
|Question Date: 2016-10-25|
Awesome question. The nervous system is so cool!
Neurons are some speedy guys. That’s why
when we pick up a pencil, it seems as if we
immediately know what the pencil feels like.
What's really happening inside our bodies is a
little more complex. The instant we pick up that
pencil, a group of neurons in our fingers are
activated, and fire, super-fast, through our
spinal cord all the way up to our brain. How
fast, you ask? Try around 75 meters per second
fast! If you were driving in a car, that would be
more than 150 miles per hour. Imagine that! But it
can get even a little more complex than that.
Only TOUCH neurons will fire around 75 meters
every second. Other types of neurons, like pain
neurons, travel much slower, around 1 meter per
second. That's like a car moving 2 miles per
hour. Beep beep! So to sum up, it depends on
the type of neuron.
Can't wait for your next question!
Thanks for the great question.
Neurons transmit an electrochemical signal called
the action potential. These signals travel
down a part of the neuron called the axon,
which is like a wire that carries the signal to
other nerve cells. On average a nerve cell sends a
signal at about 50 meters per second, which is
over 100 miles an hour! This means that when
you step on something sharp it does take some time
for that signal to go from the nerves in your foot
to your brain, although not very much time. In
fact in taller people it takes longer for a signal
to go from one area to another than in shorter
people, but the difference is too fast to tell
outside of a laboratory.
Depending on a number of factors, signals can be
sent even faster. One important factor is how
myelinated the axon is. Myelin is a fatty
substance that acts as an electrical
insulator, increasing the speed at which the
signal is sent. A highly myelinated nerve cell
can send a signal at up to 120 meters per second,
or nearly 270 miles per hour, quite a bit
faster than an airplane taking off! These quick
speeds are the basis for everything the nervous
system does, from making sense of what your eyes
see to deciding what you're going to have for
Neurons transmit their signals from one part of
the body to another through long nerve fibers.
Depending on the job of the fiber, the speed
can change a lot. For instance, some of the
nerve fibers that come from your brain and tell
your legs to move can travel as fast as 250 miles
per hour. For a signal traveling this fast, it
takes about 20 milliseconds to travel. However,
some signals are much slower like the signals that
tell you are being tickled and travel around 1
mile per hour. For this signal it can take a
second or more for you to fully feel it.
Different nerve fibers send signals faster or
slower based on how thick they are, with nerves
that send signals faster being thickened. Also
fast nerve fibers also have a protective jacket
on them called “myelin” which also makes the
signal move faster. Keep in mind that the
fastest nerve signals are still about 2.5
million times slower than electricity. So nerve
signals have electrical parts to them, but are not
The nervous system is made up of many different
types of neurons that all play different roles.
You have neurons that transmit commands to your
muscles, that respond to touch, pressure, or cold,
that respond to pain, and more!
Each neuron has its own speed it transmits
impulses at. Muscle command neurons
have one of the fastest speeds (80-120 m/s) which
makes sense because during running or other
physical activities we often need to make quick
adjustments to how we are running and what are
body is doing. At that speed it would take
under 9/1000 (.009 or nine thousandths) of a
second for a signal to get from your brain to your
Other neuron speeds vary from .05-2.0 m/s
for pain/warmth to 3-30 m/s for touch and
pressure. If you have ever grabbed something
hot on accident and it has taken a second to
realize it, that was caused by the slower neuron
speed of pain/warmth neurons.
The speed of the neuron likely depends on
the importance of a quick response. If a
muscle command neuron worked at the slower speed
of a pain neuron (which happens for some medical
conditions), it would be very difficult to walk or
keep balance. On the other hand, the slow rate of
pain neurons doesn’t result in any major loss of
function, so those neurons can be slower.
Overall, each neuron type has a different speed
they operate at in order for the nervous system to
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