You Can Understand The Nervous System: Lesson 1
I have a confession to make, one more than one occasion I have caught myself becoming frustrated with a fellow MSer for being misinformed about what MS is or why some treatments do or don’t work. Then I realized how unfair my frustration was. My first reaction to my diagnosis was to go on an information binge and learn everything about it that I could. However, I also had nearly a decade of training and tens of thousands dollars worth of education in human biology, anatomy, physiology, and pathology. I can’t even imagine how difficult it would be to understand neurology without any of that prior knowledge. After all, even some of the nurses and doctors I know recoil at the thought of neurology. It’s a difficult topic to learn and master, but I think all of you will be naturals since you live it everyday. After all, firsthand experience is the best way to learn! So through a series of posts I want to attempt to teach the major concepts to anyone who desires a deeper understanding of neurology, or for anyone who’s ever had an MS symptoms and wondered “what in the world was that??”.
So first I’ll cover the basics: what the nervous system does, and what the components are. Easy enough right? Right!
The main role of the nervous system is to organize and keep track of every cell in the body. It’s the drill sergeant of the body, and without it everything would be chaos. Of course the brain can’t pick up a megaphone and yell out orders, so commands are given by the nervous system by releasing chemical or electrical signals which travel from cell to cell until the command is carried out.
The nervous system is constantly gathering information and reacting to it. For instance, if you went outside in the middle of the winter without a coat on nerve endings in the skin would signal that you are cold and then your body would react by shivering to try to warm you up. The process starts with sensory nerve endings in your skin reacting to cold weather and a signal is sent up to the spinal cord and into the brain. The brain quickly recognizes the signal as cold and figures out that shivering is the best way to respond so it quickly sends signals back down the spinal cord into the muscles to make them shiver. All of this happens in the blink of an eye in a normal person. Another example is touching a hot stove. The skin feels the heat, the sensation travels up the nerves into the spinal cord which sends signals back down to the muscles that make you quickly pull your hand away, meanwhile your brain processes the incident which makes you go “ouch that was hot!”. This is what is known as a reflex.
Nothing that we do is “automatic”. Every task has to travel up nerves to the spinal cord to the brain and back down in order to happen, it just usually happens so fast that we don’t realize that it is actually a complicated process. Amazing stuff!
The nevous system can be divided into to main parts, the central nervous system (CNS), and the peripheral nervous system (PNS). Just think of it as the central hub and then it’s branches. The CNS is the brain and the spinal cord which form the main core of the nervous system, and the PNS are the nerves that branch off to the organs, glands, muscles, and skin.
The PNS has sensory nerves that gather information from skin, muscles, bones, joints, and organs such as the heart, lungs, stomach, and bladder. The information gathered from these nerves is taken to the CNS for processing and further commands. Once the commands are issued they travel through the PNS’s motor nerves to glands and muscles which carry out the commands. This is the basic principle behind our voluntary bodily functions, and it is also where communication breaks down and problems start to occur in people with MS. Take bladder problems in people with MS as an example. Nerves sometimes “over-sense” and signal to our brain that the bladder is full long before it really is, resulting in the nearly constant urge to have to pee. Sometimes the nerves “under-sense” and don’t tell the brain that our bladder is full and then it get filled past capacity and results in accidents (or incontinence). Then of course sometimes we know we have to pee really badly but our muscles are weak and we either can’t hold it for very long or we can’t get the muscles in our legs to move fast enough to get us to the bathroom in time which also results in incontinence.
So that’s the basic overview of the nervous system, not so intimidating right? In lesson 2 I’ll cover everything you need to know about how nerves really work, and what goes wrong in MS.