You know, the body produces it's own electricity because. It's mostly because of that Sasuke can access lightning easily, especially since it's his elemental. Also, any number of ninjas elemental to wind can channel it through a sword, kunis and whatnot. Not very different than using lightning. When it comes to making sense in Naruto canon, there is always some kind of logic involved with science. And science is a huge part of there world. Kinda ironic seeing as people who wield powers turns to science rather than religion.