The Ecology of Humans (19) The Nervous System

The Nervous System

The nervous system is an energy system in the body. ~ American massage therapist Sandy Fritz

Vertebrates have backbones housing a spinal column. The vertebrate nervous system is conveniently understood as having 2 primary aspects: the central nervous system and the peripheral nervous system. This is a conversational distinction, as these systems are fully integrated.

By the end of the 18th century the nervous system had been completely dissected, with the prevailing model that the brain and spinal cord act as a central division, and the body’s nerve network a peripheral division.

The peripheral nervous system transfers messages from sense receptors to central processing, and takes messages from central to internal operators, such as muscles and glands. This is a simplification, because all organs are both sensory in providing information to central and subject to autonomic control from central. Mental stress, for example, is pervasive throughout the body. The peripheral nervous system is long known to be plastic, as healing from a wound reconnects feeling from once-severed nerves.

The central nervous system – brain and spinal cord – comprise command central. Scientists long regarded the central nervous system as lacking plasticity. Ignoring glia as meaningful, neurobiologists only studied nerve cells, thus missing what would have been obvious given unbiased observation.

Conventional dogma had long been that the human adult brain could not produce new neurons. That is true only to the extent that neurons themselves cannot regenerate.

Only in the late 1990s was the dogma of “no new brain cells” shot down by irrefutable research that adults get fresh batches every day. But this re/generation is accomplished by glia growth – gliogenesis – which is mostly of astrocytes (a glia cell type), with new neural connections as an accompaniment.

Freshly minted astrocytes morph into neurons as required. The nerve cells that make up 10% of the brain are simply communication conduits.

Glia are active during mentation and manage both brain processes and nerve cells. Neurons are not the key player in physiological processing that has long been supposed. But we start there.