The nervous system sends information to your muscles to tell it how to manipulate the skeletal system to get whatever job you need done. Therefore when picking up something, pressure and touch receptors (nervous system) send signals to the brain about the object and how much pressure to apply. The brain informs the muscular system which, with the help of the skeletal system, picks up that object. It's a bit oversimplified, but that's the about it. Source(s):