Why is it okay to show a person getting decapitated on tv, but it's not ok to show a naked woman.?

I'm not trying to sound like a perv or anything. But seriously, why is it okay to show someone getting their brains blown out or someone getting their head chopped off, but showing nudity on tv is a big deal. I was watching "Blade the Series" on Spike and they showed a guy get his bottom jaw ripped off of his mouth, you could see the whole thing. How is that allowed on tv, but showing a nude woman is unheard of. Personally I find the blood and guts more offensive.