The living tissue aspect has always been problematic: as it is the organs in a given body that metabolize and transfer the nutrients necessary to mint epidermal matter. But, you know, there's a myriad of pickable plot holes in 'Terminator' to carp about. For instance the idea that only organic matter can pass through the time stream...and yet the terminator, consisting predominately of metal just skates right through the fifth dimension, no big deal. Whereas Kyle Reese couldn't even be bothered to take so much as a cod piece. And it's like Cameron knew his science was utter crap, because during the interrogation bit when the dectectives pick apart Reese's time theory he eventually just yells, "I don't know! I didn't build the fucking thing!"
I don't know. I mean these are all valid questions: I get that it's a B-movie blockbuster but come on, I don't think it's too crazy to ask a franchise to follow its own rules.