Your body is controlled by nerves. The Brain sends signals through the spinal cord and out to the body via peripheral nerves. This breaks your nervous system into two geographical components – The central nervous system (CNS) made up of the brain and spinal cord and the peripheral nervous system (PNS), the nerve fibres that travel away from the CNS (afferent fibres) and into the CNS (efferent fibres).
The nervous system is then broken into a further two components that differ in which nerves control certain functions. The Somatic nervous system control movement, and give information about the muscle, skin, ligaments, tendons, and bones. The autonomic nervous system regulates certain body processes, such as blood pressure and the rate of breathing, digestion, and sexual function. This system works automatically (autonomously), without a person’s conscious effort.
Anatomy of the autonomic nervous system
The autonomic nervous system is the part of the nervous system that supplies the internal organs, including the blood vessels, stomach, intestine, liver, kidneys, bladder, genitals, lungs, pupils, heart, and sweat, salivary, and digestive glands.
The autonomic nervous system has two main divisions:
After the autonomic nervous system receives information about the body and external environment, it responds by stimulating body processes, usually through the sympathetic division, or inhibiting them, usually through the parasympathetic division.
An autonomic nerve pathway involves two nerve cells. One cell is in the brain stem or spinal cord. It is connected by nerve fibres to the other cell, which is in a cluster of nerve cells (called an autonomic ganglion).
Nerve fibres from these ganglia connect with our internal organs. Most of the ganglia for the sympathetic nerves are located just outside the spinal cord on both sides of it. The ganglia for the parasympathetic division are in or very near to the organs they connect with.
Function of the autonomic nervous system
The autonomic nervous system controls internal body processes. Examples include:
- Blood pressure
- Heart and Lung function
- Body temperature
- Balancing electrolytes like sodium and calcium
- The production of body fluids (saliva, sweat, and tears)
- Going to the toilet (1 and 2) and sexual response.
Many organs are controlled primarily by either the sympathetic or the parasympathetic division. Sometimes the two divisions have opposite effects on the same organ. Eg, the sympathetic nerves increase blood pressure, and the parasympathetic nerves decreases it. The two systems work together to keep the body working within its normal limits.
Autonomic Nervous System
Generally, the sympathetic division will prepare the body for stressful or emergency situations – fight or flight responses.
Eg. It may increase heart rate and the force of heart contraction and widens (dilates) the airways to make breathing easier. It causes the body to release stored energy. Muscular strength is increased. This division also causes palms to sweat, pupils to dilate, and hair to stand on end. It slows body processes that are less important in emergencies, such as digestion and urination.
The parasympathetic division controls the body processes during ordinary situations.
Eg. It conserves and restores. It slows the heart rate and decreases blood pressure. It stimulates the digestive tract to process food and eliminate wastes. Energy from the processed food is used to restore and build tissues.
What does this all mean?
As you can probably see the human body is an amazing machine. It works within extremely specific parameters to keep our bodies functioning at their best. Any deviation from the mean point is identified and responded to by the nervous system.
When a chiropractor adjusts the spine, it can affect how these neural messages are transferred in and out of the CNS. A vertebra that has become restricted and locked will irritate nerve roots reducing the function of that particular nerve.