When a person actually dies, what happens is that a group of cells sends out the signal through cell communication to commit apoptosis, programmed cell death, throughout the body before dying themselves. Scientists think that if they can figure out a way to halt this process, many lives will be saved, but we are still a long ways away from being able to do something like that.

In the meantime, death is only a shadow cast by life. It is nothing to fear because, after we die and are redeemed, we will reach a glorified form thanks to God.