@First comment: Duh, Jester, the ability HAS to take care of all of the technical capabilities, otherwise even the most basic abilities wouldn't exist. Just because you can't personally make sense of it, doesn't mean it doesn't make sense. I mean, can you just automatically make sense of why magic works?
ANYWAYS, the ability basically preserves them exactly as they are supposed to be, with the exception (maybe) of aging and metabolic processes and movement). This means that the user's body subliminally maintains perfect homeostasis, to the point that the only thing capable of altering his form is a divine being or his own subliminal regulation of autonomic body functions.
@Second comment: What from the deepest depths of Hell are you talking about?
“…Judge not what a man has done, but judge what he could have done if he was a different bloke altogether. For art thou a leper? And a leper can changeth his spots…” --Rudy Wade, Misfits (Series 4, Episode 8)