"According to Neurogenetics at the University of Tennessee Health Science Center, the human body has 95 to 100 billion neurons or nerve cells. The brain alone has at least 85 billion of these cells, although estimates go as high as 1 trillion." It is the most important organ in the body. There is no way to understate the importance of this organ. Let's look at it another way. Stop for a moment and see/feel/hear how many things your body is doing right now. I counted six things that I notice. Seeing, hearing, smelling, sitting, etc. How many things are actually happening in your body right now as you read this? 37 thousand billion billion chemical reactions per second occur in the human body. Per second. Be glad you don't have to think about making sure all of that works. Your nervous system controls it. Almost every cell in your body is under the control of the nervous system. Imagine if you had to consciously maintain your body temperature. We wouldn't get too far. Fortunately, the hypothalamus takes care of that for us.
Image from Body World.
Bones and Nerves
Your body naturally forms a hard casing of bone around your brain and nervous system to protect it from injury. Chiropractors adjust the bones in your spine in order to create a more healthy environment for your nerves. Bones can indirectly place pressure on nerves, and even prevent cerebrospinal fluid (the fluid that flows around your brain and nerves) from bringing nutrients to the brain.
With the amount of reactions occurring in your body every second, the body needs to be a precise machine. However, things can and do go wrong in ways that you'll never notice. If an osteoclast (bone-removing cell) begins to devour your bones, it'll take years to decades before the problem becomes apparent. If the muscle cells in your heart begins to thicken, it may be years before the heart attack. For this reason, it's so important to get your spine checked regularly. It builds health in the body. Make getting adjusted a healthy habit.