How does a ileal conduit work

I have a ileostomy but my grandpa has a urostomy. I watched a video online because I want to understand it better. From what I saw it doesn't look that much different from an ileostomy. I saw that they are cutting a piece from the small intestine, reconnect the small intestine and kind of insert the urethras into the ileal conduit. What I don't understand is do they keep the blood supply of the cut out intestine intact? If not does it not "die"? Does it still transport the content (now only urine but before stool) like the small intestine via contractions? I can watch my stoma contract and expand while it's working on expelling. I wonder if the urostomy does the same. I hope I explained that enough?