broke ribbon replacing screen, what does it do?

well i replaced my screen on my iphone 4 but when i was re-assembling i broke one of the ribbons, out of the 5 main ones it was the middle one, so i went ahead and still plugged it in even tho the other side wasnt attached to any thing, turned the phone on and everything seems to be working, camera, text, phone, speakers, flash, internet, home button, touch screen and anything else i can think of. my question is what does that ribbon do? and should i expect bad things now?