Some Nervous System Basics for the Movement Enthusiast and Professional
Before diving deep into pathologies and individual situations, it is always helpful to first gain understanding in any broad topic. While certainly our bodies adapt, form various anomalies, and occasionally pathologies, it is astounding how our bodies are intended to function and do function for the majority of time and cases! Also, understanding the function of systems helps us to better understand how to work more effectively with them and also helps us to better understand when there are changes in function.
Neural tissue starts to develop in the human body at 3 weeks in embryology and cellularly, we have neurons and glial cells. Glial cells are the lesser discussed, support staff for neurons. They help to strengthen connections, support neurotransmitters, and support a well-functioning nervous system. Neurons are the more familiar nerve cells that are similar to communication highways and transmit messages by means of electrical signals. Neuroscientists are starting to study glial cells in order to better understand their impact on neurological disorders.
The nervous system is divided into two sections: the central nervous system and the peripheral nervous system. The central nervous system includes any neuron that is within the brain or spinal cord while the peripheral nervous system includes any neuron that is exterior to those two structures.
In the most essential way of understanding, the brain has three main functions: to sustain baseline living, to interpret information coming into the brain, and relay information from the brain. Information coming into the brain is referred to as afferent signals and this is also described as somatosensory. This includes the five senses: taste, smell, sight, sound and feel. Efferent signals are the information that our brain communicates to our body by means of the spinal cord and nerves. These signals are motor control which determine physically how our body will respond to the information it has gathered. For example, if we touch something soft, our brain will receive this signal afferently, signal that this is a pleasant experience, communicate this efferently and we might continue to touch that object. Or if we see a puma approaching us, our brain processes this as a threat in a part of the brain called the amygdala, and it communicates to our body to prepare to run or hide.
To maintain baseline living, we can thank our brain stem. Our brain stem keeps our heart beating, the peristalsis of our guts (the rhythmic, muscular action of our intestines that is important for digestion), and our lungs breathing. These amongst many other important functions that sustain living. There is much more to discuss with the brain stem perhaps in future articles.
Did you know that our neurons range in length from being microscopic to meters in length? This allows for clear communication across a variety of distances. In order to protect communication arriving safely to its destination, neurons are encased in cells. You might be familiar with the term “myelin sheaths” and this helps to encase a nerve signal so that it can travel the length of the cell.
Understanding these basics can go a long way in understanding what happens when things go awry. This knowledge can also go a long way in helping us appreciate what goes as intended and it’s equally important to recognize this. Most astoundingly, only in the last twenty years do we have scientific evidence supporting that the nervous system adapts, grows, and evolves. Neurogenesis is the creation of new nerve cells and neuroplasticity is the formation of new neural pathways within the brain or connecting the brain to other tissues. We formerly believed that the quantity of nerve cells we had were fixed, that they could be damaged, but we couldn’t generate more. We now have evidence to suggest that that’s not the case and that our brain makes new nerve cells and forms new pathways at all stages of life.