Zombies

Below is the zombie theory used in Risen. Although it is never explicitly stated in the movie, this is the "rule of the universe" that it was written under.

Traditionally death was considered the moment your heart stopped beating. With the need to harvest organs, this definition didn't suit medical science so the redefined death to include brain death. IE, the heart is still beating, but there is no brain response to any stimuli. So the exact moment of death is arguable depending on the school of thought you're with. For these purposes, let's assume the heart stopping is the definition.

Right before death, the body pulls in blood from the limbs to stash in the torso and brain. This is like a last ditch effort to save the body. As a result the extremeties have little blood. At the moment of death, all of the body's muscles relax. Much to the dismay of the would-be zombie, his/her birth into undeath is met with a filling of the shorts with excriment. Depending on the exact method of death the body will bear different signs.

The brain starts to become starved for oxygen and the decay process begins in earnest. Doctors argue about how long the brain can go without oxygen before becoming a total vegtable if bringing the person back is sucessful but let's just say it's somewhere between 2 and 10 minutes. Brain decay starts in the frontal lobe which is where personality and reason sit. Followed thereafter by the parts governing learned skills, followed thereafter by the rest of the brain except for the brain stem and medula oblongata (Spelling was off on that one) which is where the instinct and "things so well learned that they are instinct" reside. For example, in Bruce Lee's autoposy, they found his medula oblongata had grown to an enormous size. Scientists guess it is because he had trained in his martial arts so constantly that much of it turned into instinct. All conjecture, no one really knows for sure if this part of the brain can increase in size in proportion to the number of things wired into it. Let's suppose it is. Theory is this part can still transmit electrical signals to the rest of the body for some time although the signal is too weak to inspire movement.

Rigor Mortis sets in between 10 minutes and 2 hours depending on tempature and how much excercise the body was getting right before it got killed. Once again, depending on temperature this will last 1-3 days. Hotter=Shorter rigor mortis, colder=longer.

First off, the zombies have never filled their shorts in any movie I've seen and with good reason. I would be hard to be scared, much less not laugh if an army of angry people with crap in their shorts were running after you. We don't need a scientific reason why this is, let's just say there is some magic to the zombie condition that prevents this from happening.

As soon as the heart stops, the "zombie effect" occours. Let's say for the first 2 minutes a person is a zombie they might still be basically who they were before that part of their brain dies including the ability to speak in a slurred nature (Due to the fact that their nervous system isn't quite what it was when they were alive). During this period the zombie could move quickly if s/he desired.

Then the zombie loses the memory and congnative ability but still has the learned skills. After about 20 minutes the learned skills are gone and all that remains is the instinct and still s/he can move quickly. Could possibly drive a car, but not know where to go. The skill exists but the desire to go a certain place is not.

After an hour rigor mortis sets in. The zombie is motorized instinct capable of only the functions supported by the core. They are now slow but still capable of performing tasks that are instinct to all of us like the ability to turn a door knob to open it. Not smart enough to pick up a crowbar and pry a door open.

After a day the ability to even perform learned instincts is gone. Only the most primal existance remains.

After a few days rigor mortis has expired and although the limbs are more free to move, at this point the nervous system has decayed to a point where movement is very slow.