Remember Part I
, left us at the Tube. To talk about progressive MS, we first need to get you thinking about- how things in the body are being affected so that we can build a final picture and then talk about solutions.
The Nerve Network is made up of clusters of nerves that connect the brain with every bit of the body. Just imagine that this is an underground network with many tube lines each with a destination to a different part of the body.
The information is sent from the tissues such as the bladder, muscles etc. to the brain via the spinal cord and then the brain transmits information back to the tissues telling them what to do.. So sensors in the skin may detect when a finger goes near a flame. The sensors send information to the the brain “Ouch thats hot” the brain sends the command “move” back to the muscles in the hand and arm. Therefore you don’t burn yourself.
The information is sent by electrical energy along the nerves. This can be viewed as Tube Trains (nerve impulses
) travelling along tube lines (axons
of the nerve), surrounded by a tunnel (myelin of the nerve).
Whilst many of you MSers know this already, in case you are not familiar (see video links in previous post
). The nervs impulse (tube trains) transmits its information from the head of the nerve
called the soma
, down the axon (nerve body-tubes lines) of the nerve to the nerve terminals
or nerve feet. The nerve impulse must then must jump from the feet to the head of the next nerve to keep the impulse going. This space between the nerves is called a synapse
(interchange between differnt lines). This occurs as nerves do not stretch from one tissue to another. It is a relay race using many different nerves (underground network).
The impulse travels down the axon like a wave by moving chemicals with an electrical charge (passengers), called ions
, out of the nerve whilst letting others into the nerve. Therefore in this scenario passengers (see little people on the platform below) need to get on and off at the stations for the trains to travel and for the underground network to function. To speed this process of moving this impulse down the nerve oligodendrocyte
round the axon (tube tunnel). This is a bit like the plastic insulation round an electrical wire. When the wire gets stripped of this insulation as occurs in MS, short circuits occur and the wire can sometimes burn out. There are gaps between individual myelin wraps called Nodes of Ranvier
(Tube Stations) and allow the nerve impulse to jump from one node to the next and allow the nerve impulse to travel quickly. This process is known as saltatory conduction
. When the myelin is removed the nerve impulse travels very slowly.
Now you have got idea of the nerve network (The underground), we can ask what can ask what happens when a tube train breaks-down?
To be continued TTFN
If you don’t like this approach try the Prelude