Dear Jude,<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /> I was thinking about your questions comparing the blood vessels to the nervous system. Im no expert on the nerve connections in the spinal cord, but have had a few classes wherein we studied the nerve connections in the brain, so maybe I can help a bit. With the nervous system, each nerve touches AND is touched by other nerves as well as connecting with receptors. So its not just like A touches B which touches C. But maybe X, Y, and Z also touch C, and each one may have a DIFFERENT input (inhibitory or excitatory, and to varying degrees - meaning they may either make the sensation stronger or weaker, to put it simply). Then on top of that C might be connecting with various other nerves and/or sites and its influence is felt by them. So its a MASS of connections, not just channeling something (like blood) but having an influence that is a COMPOSITE of all the connections made to it. This is why psychotropic meds are iffy b/c scientists have only just begun to understand some of the connections and to understand just what a certain med will do to a certain individual is impossible to predict.. I once said to my psychobiology professor that it seems like the main thing I had learned from my classes was that we basically dont know hardly anything (compared to what there is to know). He said, Exactly. That was one of the main points of the class! So to mess with the blood vessels in a cut and paste manner only affects a system of channeling blood from one place to another, even though it may branch off at places. But with the nerves - which are already different in that they often dont regenerate themselves like other cells do - to mess with them is like messing with an electrical system when you have no idea what the different connections are or how theyll be affected. And of course, thats if cutting and pasting didnt kill them in the first place, which it very likely would. Someone with a more scientific vocabulary than I command could probably explain it better, but I think this will convey the general idea. Hope it helps a bit. Sally
