As security or firewall administrators, we've got basically the same concerns [as plumbers]: the size of the pipe, the contents of the pipe, making sure the correct traffic is in the correct pipes, and keeping the pipes from splitting and leaking all over the place. Of course, like plumbers, when the pipes do leak, we're the ones responsible for cleaning up the mess, and we're the ones who come up smelling awful.
When we think about living donor transplant, what we're banking on is the ability of the liver to regenerate itself. Now, it's not the same sort of regeneration we think about with the starfish where we cut off the arm and it grows a new arm. With the liver, what happens is the remaining liver gets bigger, and your body knows the size of the liver that it needs, and when it recognizes that there is not enough liver, it sends nutrients and signals to the liver and says "get bigger. "