How Things Work

 It's so interesting,  how the brain works, or the mind-body connection, or the CNS-PNS,  central-peripheral .  Afferent and efferent nerves -- the same as sensory and motor nerves. Only two sorts of neurons, inward and outward, to the brain or away. Inward is sensory, information about everything other than the brain, whether within the body or from the great wide world. Outward is motor, to get things done, either muscles or organs, somatic or autonomic. Neuron axons bundled in the peripheral nervous system are nerves; axon bundles in the CNS are called tracts. 

The brain communicates with the body in only two ways -- through motor nerves or through hormones. Nerves are a direct line, like telegraphs. Hormones float through the bloodstream hoping to be picked up by cell receptors -- something like fish and nets.  Why does exercise make muscles grow? An exercised fiber becomes more receptive to hormones. Hormones are released when enough fibers are exercise. So it's central nervous system, and it's endocrinal. 

And the way the CNS develops -- the brain and spinal cord. It starts as a sort of looped tube, eventually with six parts, spinal cord and the five parts of the brain. A tube.  It's not an addition thing, this development, not one part of the brain developing, then another one, more advanced, then yet another, and so on.  It's all there, inherent in the beginning.  It all happens all at once, with all vertebrates, the way you'd blow up a plastic bag. There is no fish brain and lizard brain and mammal brain. There are just bigger and smaller parts of the brain, depending on class. A fish's cerebrum is smaller than its eyeball. A rat's cerebrum is the size of its ear. Humans' fill up everything behind the eyes and up. But it's all the same basic plastic bag -- just different shapes.

That's the body, and the brain. Not quite the same as mind, or soul. Think of it as music. Flute music. What makes it? The breath of the player? The shape of the instrument?  Both, but not only both. Music is not breath and flute -- that might very well be just noise. We are made by genetics and shaped by experience -- but we are not breath through a flute, not experience acting through genes. We are music, inspiring as well as respiring.


FW