As cells die in the body, decomposition begins to take place. The pancreas digests itself. The lungs expel fluid through the mouth. The body turns green and the rest of the organs deteriorate, including the brain. Very quickly, the body is a shell of itself. That being said, how the hell do the dead walk around? Their brains shouldnt work, so they couldnt even use their knees. But even if they could, they should be breaking apart at the knees any time they try to walk. They're not becoming something else like Seth Brundle; they're just rotting. In many movies, including Day of the Dead, zombies pull apart their victims, consuming intestines and maybe a leg here, an arm there. How does this work? Decomposition doesnt improve the strength of muscle or bone. When the zombies pull, tear and bite, they should be losing digits, hands and teeth. Perhaps this is explained away by the fact that zombie stories do not follow proper decay protocols. Science clearly ceases to exist in the realm of living dead.
