The nervous system is divided into major parts. There is the voluntary and involuntary nervous system.
The involuntary or autonomic nervous system is divided into two parts; the sympathetic system excites organs or glands (think “fight or flight”) and the parasympathetic system relaxes them ( think rest and digest). They keep each other in check and balance. It’s kind of like a teeter totter. If you have to run, you want the fight or flight system to speed up your heart etc. If you want to sleep or digest food, you want the mellow yellow nervous system to be dominant.
The voluntary nervous system is the motor nervous system which allows you to do things under your control like walk or grip something.
Both systems send information to the brain via sensory nerves and a response is returned via motor nerves. The brain receives this information by nerve cells that make up networks.
Nerves are bundles of information carrying cells that carry messages to and from the brain. They are made up of cells that interconnect.
Both voluntary and involuntary nerves go to and from the brain and exit the spine through openings between the vertebra. When one of the vertebra shift or are fixated, there is a disruption in function of the involved nerve thereby impairing the ability of the brain to regulate the tissue, organ, gland, muscle, or system involved.