We’ll discuss how cells speak with
each other and deliver communique.
This could be in close proximity or
those that are far away in the body.
Also, cells need to communicate
vital information within the cell.
And how do they do that?
These will be covered within.
There are many modes
You can come up with a lot
of these on your own.
Some of them are personal in
nature such as a handshake,
other ones involve things like a
delivered package or envelope,
or even on the internet
you can communicate very
easily with a number of
friends at the same time.
How do these communique work?
Well, one of the things to
think about with the body
is what modes of
communication does it have.
One of the more vital ones
are endocrine control.
Here, you release a signaling molecule or a hormone.
It travels around in the bloodstream and
is delivered to certain target cells.
How do you know which cells
will get the communique?
The ones with the
If you don’t have the
right receptor, you won’t
receive that information
or that signal.
Neural signals are
also very important.
Here, a neuron can signal via long projections
of axons going to an axon terminal
and then releasing a packet of information
to the cell it’s trying to signal.
These neural signals are very powerful
in that they are direct communications
rather than just releasing the
substance into the blood,
letting it travel around
throughout the body.
Here, it’s more
targeted in nature.
Now, if we move to some
more local control,
these are signaling molecules that will
signal varying cells right around a cell.
This involves passive
diffusion in which
a molecule is released
from the signaling cell
and will only be able to diffuse
in the distance around it.
Which particular cells will
receive the communique?
It’s all based
upon the receptor.
You need to have a receptor to
catch that signaling molecule.
Interestingly, there are also
times in which a cell will
want to receive the information
that it is releasing.
A good example for this, if
you’re releasing signals,
you would want to make sure you knew
how many signals were released.
You could have a receptor on the
own cell that is sending these out
to get feedback about
Now, besides sending a
you could also have direct contact
with the cell next to you.
Some of the direct contacts involve
things called gap junctions.
Gap junctions are these
that allow communication between two cells
like it’s not even leaving that cell.
So these tubes will communicate
sometimes its ionic information,
and this will allow a propagated and coordinated
response between a number of cells.
Some direct signaling can happen
via paracrine mechanisms.
For these paracrine mechanisms,
you have to have one cell that can move
around and be able to recognize another.
So the immune system is
a very good example,
where you might have immune
cells that can travel around
and recognize other cells based upon
what projections they have sticking out.
Here, it’s like a handshake,
where one cell will get up to
a close proximity to another
and if they can recognize
each other’s projections,
they might be able to bind
and signal each other.