Shock! what happens to your body when you are shocked?

I read recently, (cant remember where, which is why I'm posting) that when you are shocked by something - your body freezes so you are focused on what is happening, your eyes widen so you can take more in...anything else? There was also a bit about hormones(?) being released – so that you are ready to react.The adrenaline pumps in the body. that's why your heart starts beating harder, you breath differently, you go pale.adrenaline pumps through your body so if you need to react by punching you can keep going until you feel safe. Or you can run and keep running without stopping, but that is a bad idea because when you finish running you can go on collapse..TOINX!!