Ummm. Electrical impulses also run across the mylan sheeth (I might be mis-spelling that) that covers the nerves ... also it ripples across cells ... pluse ... yes, there's more ... it is conducted via collagen ... we litterally have electricity running to every nook and cranny of our bodies.
Some scientists are studying wether some information is passed from one part of our body to another via our electromagnetic field. There are some reactions we display that move too quickly for our nervous system to handle ... we know the information is moving because we react ... we just don't know what path that information takes.
I think its important to recognize that the concept of chi comes from an experiential understanding of the body. No one function or system relates to or is chi, rather chi is the very subtle energetic/biomolecular movement and change that is constantly taking place in your body. In the west I think we get cought up in the idea of chi being some mystical force that one has to practice in order to get in touch with, but really chi is something we are all intimately connected with at all times. When you have an adrenaline rush, it makes your body feel a certain way, the feelings and sensations that occur in that state are one manifestation of chi. But I also believe you can deepen your connection with those biomolecular/energetic changes to deepen ones state of health by encouraging more stable functioning in the body. At least this is my take.