Guillain Barré Syndrome is one of several
demyelinating diseases. Demyelinating Diseases do just what the name implies,
they demyelinate neurons. This is a very serious issue because myelin sheaths
on axons are more than just decoration. They are used to transmit impulses
quickly down the length of an axon. The speed of transmission in an unmyelinated
axon is about 0.7m/s (2mi/hr). This is about the speed that you jog. You might
think that this is fast enough because a human body is about 2 meters tall so an
impulse travelling to your feet would only take about a second or two. And you
would be partly right. This is fast enough for information that needs to be
sent to your digestive tract and other not-super-important stuff. However, if
you start to trip, you need to reposition your body within a split second. This is where myelinated neurons come into
play. Neurons innervating skeletal muscle are myelinated. This myelination
increases speed of transmission to about 120m/s (270mi/hr). So now that you can
see how important myelin sheaths are, lets talk about what it would be like to
lose that myelination.
There are two types of glial cells that assist
with myelination: Schwann Cells and Oligodendrocytes. Schwann Cells wrap around
axons in the peripheral nervous system while Oligodendrocytes hug axons in the
central nervous system. Guillain Barré Syndrome occurs when specifically the
peripheral nervous system is attacked and becomes demyelinated. The initial
symptoms of this disease include weakness and tingling in the legs. These
sensations slowly spread upwards to the upper body and arms. The brain being
unable to transmit commands efficiently to the muscles causes the weakness. It
can increase in intensity until some muscles can’t be used at all. This can be
very severe because it leads to the individual becoming paralyzed. If the
muscles used for respiration are affected, it can be potentially fatal. The
tingling is because the sensory receptors cannot transmit information to the
brain. It can manifest in an inability to feel heat, pain, and other
sensations. Or, the brain might receive weird, altered signals that result in
tingling, creepy-crawly, or even painful feelings.
It is an autoimmune disease which means that it’s not a
virus or bacteria destroying the myelin, its your own body. Sometimes, it can
be caused be preceded by an infection. A virus or bacteria could have changed
the cells in the nervous system so the immune system thinks they are foreign,
or it could have made the immune system more belligerent and care less about
what it attacks.
Sadly, there is no cure for this syndrome; only therapies
that try to lessen the intensity of the symptoms and treatments for its
complications.
This article explains Guillain Barré Syndrome in a little more
depth, as well as explains many of the complications and their treatments.
I was surprised when I found out there was more than one demyelinated disease. I actually did mine in Multiple Sclerosis which is also a demyelinated disease. With the information that you have provided about GuillainBarreé Syndrome, I know now how important is having myelin so we can actually function well. I find it horrible how there is still no cure for the demyelinated diseases. I hope that one day in the near future researches are able to find a method on how to prevent it and be able to cure it.
ReplyDeleteit is so crazy how such small tissues or organs they all have their own major role on how your neurons transmit impulses for muscle reaction.I wonder if athletes have better neurons than the average Joe. I say that because athletes have very quick reactions, how fast do the nuerons send singles to the brain compare to an average person
ReplyDeleteThanks to your post, I’ve learned more about our brain and the neurons inside it. When I read the chapter, there were still some things I was confused about, the section on myelin sheaths was one of them, I kind of understood what they were for but I was still confused. After reading your post I understand their use a whole lot better, I know now how important they are to keep our brain in tip top shape.
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