|
|
 |
Welcome to the website of the
Southwest Virginia MS Support Group
|
 |
|
|
|
|
|
|
Neurons
Neurons, also
known as nerve cells, are the body's "controlling" cells. They
perform many of the more complex functions in humans and
animals including thought, memory, control of bodily functions
(both conscious and unconscious), processing of sensory
information, voluntary and involuntary movement and
transmission of nerve signals both to and from all parts of
body.
The interactions between neurons are not only too complex
to describe in a few simple sentences but also in a whole
library of medical textbooks. Depending on your philosophical
and theological persuasion, neurons are either the location of
intelligence or the interface between the physical
brain
and the soul or spirit. Either way, it is generally understood
that neurons are the most important cells in the nervous system
and that, despite the complexity of what neurons as a
whole produce, individually they are better understood.
Each neuron has three basic parts: cell body or
soma with a central neucleus that contains most of the
DNA, one or more dendrites, and a single axon.
The Soma performs all
the basic cellular processes like protein synthesis and energy
production. Additionally, neurons have two types of extensions
known as dendrites and
axons.
The dendrites are thin, branched extensions that
communicate to other neurons via a connection called the
synapse.
The synapse works by sending special chemical signals, called
neurotransmitters, across a gap between the neurons known
as the
synaptic cleft. Dendrites carry signals towards the soma.
Axons are long, sometimes very long, extensions that carry
nerve transmissions along the length of the neuron and away
from the soma. The nerve transmission is an electrochemical
signal that consists of a depolarising current, called an
action potential.
Axons are sheathed in a smooth, fatty protein called
nodes of Ranvier.
Neurons vary a great deal both in size and construction
depending on their location. Some neurons are the longest
cells in the human body whereas others are very small indeed.
As regards multiple sclerosis, it is the neurons of the
central nervous system (CNS) that are of interest.
Specifically, MS is a disease where the myelin sheaths of the
CNS white matter become damaged (demyelination)
leading to reduced efficacy of nerve transmission along the
axons.
Most of the neurons in the human body are laid down before
adulthood although there is now evidence that some neurons do
grow in adulthood, specifically in the hippocampus region of
the brain.
Neuron links:
|
|
|
|
|
|
