The Nervous System
Have you ever wondered what makes our bodies do what they do? Why we move, talk, breathe and everything in between?
Well, there is one system of the body that is primarily responsible for driving all those things… your nervous system.
What is the nervous system?
The nervous system is a complex collection of nerves and other nerve tissues. It intertwines and interacts with all the other 10 systems of the body.
Even though it is found throughout the whole body, it equates to less than 5% of the total body mass. This makes it one of the smallest systems of the body.
This is hard to get your head around when you consider there are billions of nerve cells (aka ‘neurons’) that make up the system. It’s mind-boggling stuff!
The nervous system is made up of two main parts:
- Central Nervous System (CNS)
- Peripheral Nervous System (PNS)
Central Nervous System
The CNS is made up of the brain and spinal cord.
The brain is housed inside the skull and connects to the spinal cord through a hole in the base of the skull.
The spinal cord runs down the body and is protected by the spinal column, which is made up of numerous vertebrae (the bones of the spine).
The main roles of the CNS include:
- Processing incoming sensory information from inside and outside the body
- Sending out commands to the muscles to contract
- Sending out commands to glands to release hormones
- Acting as a control center for emotions, thoughts and memories
Peripheral Nervous System
The PNS is made up of all the other nervous tissues that sit outside of the CNS.
It predominantly consists of the nerves that travel from the brain and spinal cord to the rest of the body and back again.
There are 12 pairs of cranial nerves that travel from the brain. There are also 31 pairs of spinal nerves that travel from the spinal cord.
Various other types of nervous tissue also form this system.
The PNS is further broken down into the following parts:
Somatic Nervous System (SNS)
Also referred to as the ‘Voluntary Nervous System’, the SNS controls the voluntary movements of the body.
Autonomic Nervous System (ANS)
The ANS is further broken down into sympathetic and parasympathetic divisions.
These are the parts of our nervous system that control our ‘fight or flight’ and ‘rest and digest’ responses, respectively.
Enteric Nervous System (ENS)
The ENS relates to the gut.
How does the nervous system work?
All the above subdivisions of the PNS have a sensory part which transmits information to the brain and spinal cord.
They also have a motor part which transmits information to the body to drive an action.
For example, the motor part of the SNS drives contraction of our skeletal muscles, allowing our bodies to move.
Whereas the motor part of the ANS drives contraction of smooth muscle, found in the arteries and the gut, as well as cardiac muscle, which is our heart muscle.
The main difference is that the SNS works on a voluntary basis, as mentioned above. For example, we choose to move our arm.
The ANS, on the other hand, works on an involuntary basis. It is automatic (or autonomic, hence the name), and its actions occur without us choosing or even really knowing about them.
For example, our heart beats without us having to consciously tell it to do so.
Cool, huh?!
What is the function?
OK, so we’ve just thrown A LOT of info at you, but hopefully you are starting to see how the nervous system is made up and what jobs it is responsible for.
The main overriding job of this system is to control the internal conditions of the body so it can function correctly.
We move, we talk, we breathe… and everything in between!
A real-life example
If you’re a visual person and need to see or read a real-life example, then think of the nervous system as working like this:
You are standing at a pedestrian crossing and the green figure lights up with a corresponding beep.
The sight of the light and sound of the beep stimulate receptors in the eyes and ears. This is sensory information.
This sensory information is then relayed to the brain and processed. A decision is then made on what to do.
This is actually known as integration, if you really want to know!
The brain then decides which muscles to contract to allow you to walk across the crossing to the other side of the road. It then signals them to move.
This is the motor function.
So just remember… sensory, processing and motor, and you have the basic functions of the nervous system under wraps!
Conclusion
Right… who is ready for their exam?!
Interested in learning more about the body? It’s fascinating!
If you are keen to learn more about what we do, or even move into the field of osteopathy, please do come and chew our ears off next time you are in.
Our fantastic profession is always on the lookout for new talent.
And you get to spend your life learning about all the cool things the human body can do, as well as helping people reach their full potential!
What’s there not to love!
More on the body: Vertigo
