The following three illustrations show the different parts of the total nervous system. They are shown in the three main divisions, on the basis of anatomy and specific functions. While the breakdown is used for illustration purposes, each segment of the nervous system is interdependent and interrelated. The body is so wonderfully complex that one part often affects another part seemingly distant, remote, and unrelated. Therefore, the spine is the Doctor of Chiropractic's "avenue of approach."

#1 The Peripheral Nervous System serves to connect the central nervous system with the various tissues of the body Spinal nerves at various levels have sensory and motor connections. Messages or signals can be relayed from the tissues of the body back to the brain through the spinal cord. The spinal nerves extend outward from the spinal cord through openings between the vertebrae. Once they pass through these openings they extend great distances dividing into many branches, thus forming a complicated, intricate network reaching all the tissues of the body The peripheral nervous system is composed of Cranial nerves, Spinal nerves, and the Autonomic nervous system.

#2 The Autonomic Nervous System, or "involuntary nervous system," as it is sometimes called, governs those activities which are carried out automatically without the individual being conscious of their performance. Examples of these activities would be regulation of heartbeat, digestion of food, circulation of blood, etc. It has two divisions, the "Sympathetic" and "Parasympathetic" which in general serve to produce opposite and equalizing effects on the body to maintain it in a state of balance."

#3 The Central Nervous System, includes the brain and spinal cord The brain is encased in a hard protective covering: the skull. The spinal cord is encased in the center of the spinal vertebrae for protection The functions of the body are truly examples of engineering marvels not to be duplicated or yet to be fully understood.