All long term systems require:  

* Adequate design and structure.

* Sufficient spare capacity to function despite component failure and lack of repair.

* Possibility of repairs in event of failure beyond spare capacity. 

* Availability of spare parts at the area of need and energy to fit them.

* Removal and safe storage or disposal of redundant or failed parts.

Humans are a long term system!!

Therefore, ALL these factors apply to us and in the gradual development of Parkinson's or other neuropathological
syndromes these combine as shown below. Some of these qualities are genetically determined, ie. inherited.

Quality of nervous system                   Quality of circulatory system

including overcapacity                         including thickness of vessel

and collateral paths and                       walls, layout and collateral  

innate ability to repair.                         routes and heart efficiency.  

All these are important

Quality of energy supply                      Quality of nutrient supply

depends on circulation to                    depends on gut efficiency,

deliver and replenish and                    absorption, toxin production,

also remove waste products               competition for nutrients and

                                                                    good circulation to deliver.        

Long term gradual failure of one or more of these is likely to result in slowly increasing brain damage only apparent after many years when all spare capacity has been used up and sufficient self-repair is not possible.

(Copyright © Andrew Carmichael 2007)