One statement that I use alot is, "All the world's a voltage divider." When you start thinking of the human body playing a part in a voltage divider, it should probably be considered as a highly variable resistance. One day I had my Fluke 87 out and asked everyone to test for resistance by pinching the probes, one in each hand. Most results were pretty close but for one guy, whom we'll call Dave "the reptile". It was surprising to see his skin resistance more than twice as great as the highest of the rest of us. It would not be unreasonable to assume that Dave might have better resistance to electrical shock considering our observations that day. But you really need to think of humans like the reverse of the nichrome that you were trying to figure out. The nichrome's resistance per given length increases as you flow more current and heat it. Once you start getting shocked, bad things start happening that will tend to lower the body resistance, such as ionizing body fluids and increased sweating.
As far as the shock sensation is concerned, I could see more sensitive parts of the body being able sense a current flow that other areas wouldn't.
Joe

[This message has been edited by JoeTestingEngr (edited 12-23-2005).]