explain
pain
2
section
37
page
Sensors in the neurones to the brain
Some of these sensors in the next neurone act for day to
day dangermessages: some are special memory sensors;
some are reinforcing sensors and some sensor activity
can be reinforced by activation of the immune system.
When your whole body is under threat, for example
when you have the flu, increased sensitivity is a
common feature.
A dangermessage will pour particular (let’s say square)
chemicals into the synapse. The square chemicals are
the keys to unlock the square sensors on the second
neurone. When the excitement level of the second
neurone reaches the critical level –WHAM! – the second
neurone sends amessage up to the brain. Thismessage
says ‘Danger!’ This is why these second neurones are
called ‘second order nociceptors’. We call them danger
messenger neurones.
Sorting at the synapse
The synapse in the spinal cord is an important sorting
site - a bit like a post office. The inputs and outputs of a
post office are constantly changing. If there is a party in
the post office and everyone is excited, all sorts of
messagesmay pass. However, this is just a regional post
office and, to some degree, its activity is controlled by
the central post office (brain). In fact, the central post
office (brain) can even shut down the regional office
(spinal cord) via a very powerful internal danger
management system (the neurone from the brain).
The drug cabinet in the brain
How is that done? A pathway comes down from the
brain tomeet any arriving impulses. Have no doubt
about the strength of this pathway, so powerfully shown
in the amazing pain stories. It must bemore powerful
than any drug you can inject or ingest (and no side
effects or prescription required). It allows a flood of
chemicals (happy hormones) such as opioids, serotonin,
and somemorphine which are all different in shape and
which therefore activate different sensors. These sensors
actuallymake positively charged particles
leave
the
neurone, whichmakes it
less excited
, which in turn
makes it less likely to send amessage. So, the
descending input dampens down the alarm signals.
Yes, with this system, you canwin the grand final or the
world championships or cook for twenty while still
carrying injuries. The best way to power it up is to have
knowledge and understanding.
