Human Body - The Nervous System
Introduction to the Nervous System
Your nervous system is quite a complex body system and serves many more functions in your body than you may currently be aware of. This article will give you a simple explanation of the nervous system and it's subcategories, supplementing your other learning resources by condensing the immense amount of information into a brief rundown.
The Nervous System - You may like to refer back to this picture throughout your reading
Central Nervous System
Your Central Nervous System (CNS) is made up of your brain and your spinal cord.
It is basically the control centre of your nervous system.
Your spinal cord has both an ascending pathway and a descending pathway. The ascending pathway delivers messages to the brain for processing; For example, if you touch something hot there will be a message conveyed that gets sent along your nerves, through your spinal cord and up into your brain so that it can then decide what to do about the information it has received. After the message has been received and interpreted by your brain, the descending pathway in your spinal cord will then carry the information, which has been sent by the brain, back down the spinal cord, and in this instance the message would be sent to your skeletal muscles telling them to move your hand away from the source of heat. It is a very quick process!
Peripheral Nervous System
Your Peripheral Nervous System (PNS) is made up of all the nerves in your body, except for your brain and your spinal cord.
The PNS is a messenger of sorts. It sends sensory information to the brain, called the afferent pathway. The sensory information comes from all the many different receptors in your body, each sending a multitude of messages. For instance, you have receptors for touch, temperature, taste, smell, sight - and those are only a few!
Not only this, but the PNS also sends instructions from the brain to other parts of the body using the efferent pathway. Under this pathway there is many other subdivisions of the PNS that each have their own important functions. There is the somatic nervous system, the autonomic nervous system, and it's subdivisions the sympathetic nervous system and the parasympathetic nervous system.
The PNS has nerves that run off of the spinal cord in different places; The nerves that run off of the top portion of the spinal cord tend to serve some of the more vital body processes, such as heart and lung function. While the nerves lower down the spinal cord control body processes that your body can survive without. Such as the movement of your legs.
Now we will take a closer look at the different subdivisions of the Peripheral Nervous System.
Somatic Nervous System
Your somatic nervous system is basically what controls all of your voluntary movement.
Autonomic Nervous System
Your autonomic nervous system is what controls all of your body's involuntary actions within your peripheral nervous system.
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Sympathetic Nervous System
Your Sympathetic nervous system is most often described as your fight or flight response.
Parasympathetic Nervous System
Your parasympathetic nervous system is what is commonly referred to as your rest and digest function.