The nervous system, regulates rapid muscular and secretory activities of the body, whereas the hormonal system (endocrine) regulates mainly the slowly reacting metabolic functions. The central nervous system consists of the brain, spinal cord and nerves emanating from them.
The Brain and the Cranial Nerves:
The brain consists of two hemispheres. The left controls the right half of the body and visa versa. This “crossover” is important to therapists in that it is the major exception to zone theory.
The brain is the central computer that controls both the voluntary and involuntary system of the body.In other words it controls the central nervous system and the endocrine system, both of which jointly control the complex activities of the whole body. There are twelve pairs of cranial nerves arising from the brain and passing through the holes in the skull. Some of the cranial nerves are only sensory (taste, smell, sight and hearing), but the majority are motor nerves. Probably the most important of the cranial nerves is the vagus nerve. It is the largest nerve in the body supplying the heart, lungs and abdominal organs.
Spinal Cord and Spinal Nerves:
The spinal cord is the continuation of the brain below the skull. It is a column of nervous tissue enclosed in the spinal canal, a tunnel in the backbone. The nerves originating from the spinal cord are channels for conveying information from the peripheral nerves of the body and to the muscles and glands. The cervical nerves control the neck and arms. The thoracic portion provides nerves to the chest. The lumbar nerves are distributed to the lower extremities, the legs and feet, and the sacral nerves mainly supply the organs of the pelvis, the pelvic and buttock muscles.
The spinal nerves are named and numbered according to the vertebral divisions of the spinal column into cervical, thoracic, lumbar and sacral segments. The spine has seven cervicals starting with the atlas-axis, the first and second cervicals which is what the head pivots on). It ends with the seventh cervical, a protruding vertebrae at the base of the neck. The seventh cervical effects everything down into the fingertips. From the seventh cervical down are the twelve thoracic vertebrae each carrying a pair of ribs. These end at the waistline which marks the beginning of the five lumbar vertebrae. This is the lower back. The lower back has a profound effect on everything in that region such as the reproductive organs, digestive tract and the lower limbs. Below the lumbar vertebrae are five fused vertebrae which form the sacrum and the vestiges of the tail, the coccyx. This area can affect many parts including the head.