There was a recent article in the New York Times that sums this up exactly. A man designed a prosthetic arm which he wired to his shoulders so that it could move just as a regular arm could. But not just in the way the dude from ‘The Fugitive’ had it. I mean it moved just like a regular arm. He could move the limb simply by thinking. His brain sent a signal to his arm to move, and it moved. It’s sorta like how Luke got his hand chopped off by Darth Vader only to have it replaced. Pretty cool.
All technological marvels aside, all our organs and limbs function in the same way. Our brain tells us how to operate. The rest of our organs have functions which provide us with the necessities in order to exist. Our lungs are designed to collect oxygen and send it through the blood stream. Our stomach digests vital nutrients and sends them through the blood stream. Our kidneys and livers also have specific functions to prevent the blood from becoming too ‘dirty’ so to speak. We have vocal chords in order to better communicate. We are even proportioned in just the right way in order to maximize utility (opposable thumbs come to mind here).
I could go on, but you get the point. This is a simple point anyway. Simply stated, our bodies are all well-tuned machines, which run all the time, 24 hours a day, 7 days a week.