There is a large safety literature about electrocution. From my days in MRI, the basic thing I learned about electricity and the human body is that the interior is basically saline (inside a cellular structure) that is fairly low resistance compared with the resistance through the skin, but the skin resistance is a strong function of skin moisture. Back in high school, we played lie detector using only a Simpson 260 in its highest resistance setting, safely measuring the resistance between hands (pinching the probes between thumb and forefinger), to see if lying made the skin sweat.