Ready, Signal, Fire: Nerve Supply
Every activity that your body performs is based on the activity of your nerve system. Whether it’s the rhythmic contractions of your heart and digestive systems, or the rhythm of your golf swing, the activity of your nerve system determines how your body functions. Your nerve system integrates the activity of every cell, tissue and organ system in your body.
The language of the nerve system is the signals that are sent across nerve fibers: the nerve impulse. In many ways, nerves act as bundles of wires that carry signals in order to transmit information. As each one of the nerve fibers in the bundle sends an impulse, or fires, a signal is transmitted so that your body is always acting in harmony. As nerve impulses reach their destination, the signals are like on/off switches that regulate and integrate every activity of your body.
The firing of nerve impulses strengthens and develops the pathways along which the impulses travel. In other words, repeating a phone number, or the motion of a free throw, strengthens the nerve pathway so that it is more powerful in the future. In this manner, nerve fibers create new pathways and reinforce existing ones to create the ability to learn, move, feel and think.
Nerve Supply to Your Brain is Critical
Millions of bits of information are gathered from every part of your body that then travel through the spinal cord to your brain. This input of nerve supply to your brain is critical for your brain to function. So much so that the uppermost sensory input to the brain, the fifth cranial nerve, is the dividing line for brain activity. If an injury above this point were to prevent sensory information from reaching the brain, it shuts down. Were the same injury to the brain to occur below this point, the brain remains active.
In other words, although we know that the brain is a supercomputer that runs the body, it is just as true that the nerve supply from the body is what runs the brain. Your brain runs your body, but your body fuels your brain. And according to Dr. John Medina, director of the Brain Center at Seattle Pacific University, the most important of this fuel is movement. Movement, he says in his 2008 book Brain Rules, “acts directly on the molecular machinery of the brain itself. It increases neurons’ creation, survival, and resistance to damage and stress.”
Movement, Nerve System and Your Sixth Sense: Proprioception
Your sixth sense is an essential function of your nervous system called proprioception. It is how you know where to place your feet when you walk, how a batter is able to swing a bat into the path of an incoming ball, and how you can touch both of your fingers together behind your head without looking. Proprioception is your body’s ability to be aware of where it is in space.
Amazingly, the vast majority of the information traveling across your nerve system is below the surface. Furman and Gallo, in their textbook The Neurophysics of Human Behavior, report that throughout the nerve system, there are trillions of bits of information flowing through your nerves. Of these, we are consciously aware of around fifty at any one period in time. The constant evaluation of movement information through the proprioceptive part of your nerve system is similarly behind the scenes. It has a powerful influence on your health, however.
The authors of this program, wellness chiropractors, have seen firsthand how proper function of the nerve system and proprioception is an essential element for health through working with patients, as has been seen by chiropractors for over 100 years. Roger Sperry, PhD, received the 1981 Nobel Prize in Medicine for his work in brain research. This is how he described how important the impact of proprioception and its contribution to the essential element of nerve supply was to overall health. “Better than 90 percent of the energy output of the brain is used in relating to the physical body in its gravitational field. The more mechanically distorted a person is, the less energy available for thinking, metabolism and healing.”
The unconscious understanding of the body’s positions and movements has always been the critical element of every moving animal species. Without it, it is impossible to perform the basic functions of finding food and water, shelter and procreation. Because of this, the proprioception component of your nerve supply is hardwired into regulating your body’s ability to handle stress.
Stress, and Your Nerve System
Ultimately, it is your nerve system that is responsible for handling stress. Stress comes from three categories of sources: chemical, physical, and mental. That is, stress results from unhealthy choices in your fuel, air and spark. Once your body encounters stress, however, there is a common response from your body.
The physiologist Hans Selye was the first to coin the term stress just over fifty years ago. The hallmark of the response to stress inside your body (the stress response) is the release of stress hormones. As discussed below, the release of these hormones is controlled by your nerve system. When your body perceives something as a stress (read: your nerve system senses a stressor), it sends signals to release hormones. These signals are controlled by a part of the nerve system called the sympathetic nervous system. Adrenalin and noradrenaline, also known as epinephrine and norepinephrine, along with cortisol are the initiators of a system-wide stress response in your body.
Fight-or-Flight, Rest and Repair, and Your Nerve System
Just as being awake and being asleep are two separate and distinct states, being stressed and being in a state of healing and repair are two separate and distinct states. When our bodies are in a state of stress, the hormonal release stimulated by the nerve system prepares the body for a state of activity. This means tearing tissue down, preparing to burn energy, and preparing to move. Blood is sent to muscles, away from organs, blood pressure rises as vessels tighten, digestion slows, and immune responses weaken as the body prepares for action. This feeling of stress, often referred to as the fight-or-flight response, is directed by the sympathetic nervous system.
The sympathetic nerve system is used by your body in response to stress, or, in other words, anything that your body perceives as a threat. Acting intelligently, your body’s response to threats is to prepare for action: fight-or-flight. Even thinking of a stressful event will cause you to experience the influence of the sympathetic nerve system in your body.
To do this, however, there is a cost. Spending energy to deal with a threat means halting the activities of rest and repair. The sympathetic nerve system activity has an opposite system in your body dedicated to rest and repair called the parasympathetic nerve system.
Your parasympathetic nervous system is responsible for the activity of digestion, relaxation and reproduction. This is the system your body activates during times of safety for healing, tissue repair and procreation. In order to heal and repair effectively, you want to be in a state of rest and repair.
Research over the past twenty five years has shown how far-reaching the influence your nerve system is on the function of two other “super-systems” inside your body: your immune system and your endocrine, or hormonal, system.
The Hard-Wired Connection Between Your Hormones, Immune System, and Your Nerve System
Prior to about twenty five years ago, mainstream science did not understand the intimate connection between the immune and nerve systems. Patients of chiropractors, however, reaped the benefits of improved nerve system function for decades before this. See this example of life-saving results patients of chiropractors, doctors trained to remove interference to nerve system function, had during the flu pandemic of 1918.
In fact, every immune organ in your body is richly influenced by communication from your nerve system. Immune organs located in your body, including your network of lymph nodes, your thymus, spleen and bone marrow, and also most importantly in your digestive system, have their activity directed by your nerve system.
This connection is also one of the underlying mechanisms that explains why you are more susceptible to becoming sick when you are stressed. During a period of stress, you shift into a more sympathetic fight-or-flight mode, promoting the release of stress hormones. Chronic stress hormone release makes you more susceptible to illness.
Today, research showing how the immune system, hormonal system and nerve system are hard-wired together continues to grow more and more. To read more, check out these links on this growing field of psychoneuroimmunology.