While other systems and organs of the body control individual functions, the central nervous system does many different jobs at the same time. For example, the circulatory system supplies oxygen to the rest of the body. To do this, it is the job of the lungs to oxygenate the blood and the job of the heart to pump it. But the central nervous system controls both the lungs and the heart while it is busy controlling many other things as well. It controls all conscious movement (e.g., speech and walking) and unconscious involuntary movement (e.g., blinking and breathing). It also controls sleeping and waking, hunger and thirst, proprioception and balance. The central nervous system is the core of our thoughts, perceptions, and emotions.

Innervation of the Internal Organs

Innervation of the internal organs"In addition to the control of voluntary movement, the spinal cord also contains pathways of the sympathetic and parasympathetic pathways. These are the pathways involved in the fight-or-flight response to danger and in the control and regulation of bodily functions. These functions include the regulation of hormone release, movement of food through the stomach and intestines as well as the sensations coming from and muscular control going to, all the internal organs. The diagram to the right is a simplified illustration of these pathways and the level of the spinal cord projecting to each organ. It is best to enlarge this image to see the detail better.

Background on the Central Nervous System

Because the CNS is so important and cannot repair itself easily, it is very well-protected. The brain and spinal cord are more protected than any other organs in the body. The main line of defense is the bone of the skull and vertebra which makes a hard, tough physical barrier to protect the brain and spinal cord from injury. Just below the bone is a fluid filled space to provide shock absorbance. Unfortunately, this protection can be a double-edged sword. When an injury to the CNS does occur, the bone of the skull and vertebra become a barrier to the soft tissues of the brain and spinal cord, which swell after an injury. This swelling (called "edema") causes pressure because it occurs in a constrained space. This swelling and pressure can actually make the initial injury worse unless the pressure is rapidly relieved. Additionally, an injury severe enough to fracture the bone can result in further damage caused by the bone fragments themselves and the possibilty of infection.Related: Sports Injuries