Sunday, May 4, 2008

Nervous System Basics: Part II: UBIQUITY

There are 8 considerations presented by the author on how to contemplate the nervous system. They are,
1. Ubiquity
2. Unity
3. Centralization
4. Specialization
5. Purposefulness
6. Uniformity with Versatility
7. Plasticity
8. Chemical Message Coding

This is the first. From p. 331, Vol III, Encyclopedia of the Human Brain, author Jay B. Angevine:

With 100,000 miles of nerve fibers the nervous system rivals the vascular system. Both pervade the body and function in harmony. By nerve impulses or circulating red and white cells, glucose, hormones and immune principles, they integrate body activity, protect the body, enhance its performance to met stress or demand, promote its growth and nutrition, and maintain its tone and vigor. The trunk and branches of both systems reflect body form. If either system and no other part of a person were visible, he or she would be recognizable. Density of innervation varies as the value of parts to sensory discrimination or motor control. In well-innervated areas (lips, fingertips) stimuli are sharply discriminated as to modality, intensity, and location, but in sparsely innervated areas (flanks, legs) these are less defined. Similarly, muscles vary in the ratio of motor neurons to muscle fibres. The higher the ratio, the more precise the control of the muscle and the movement it serves (a motor neuron may excite 2000 muscle fibers in a limb muscle or as few as 5 in extrinsic ocular muscles)."

I don't know what else to say. To me this is a beautiful image of a filamentous system which comprises only 2% of our physicality, but which regulates 100% of our function.


Kent said...

Learning more about how we are made evokes awe and wonder. Thanks!

dermoneuromodulator "neuroplastician" said...

You're welcome Kent. It certainly evokes awe and wonder in me too. It's probably really all that ever has, in the long term. :)