You can tell I don’t watch Grey’s Anatomy (or read Gray’s Anatomy)

One of my team is a big Grey’s Anatomy fan and told me about McSweaty, a nickname given to one of the doctors. There’s also McDreamy, McVet, McHappy, McBashful, McDopey and Doc.
   Oh, sorry, it’s McSteamy. 
   Apparently, this whole thing with putting Mc in front of a name began with this show, even though Patrick Dempsey’s character has no Scottish blood. It could have actually been Joseph McGinty Nichol, a.k.a. McG, the music video and movie director, who started this. But I guess that explains Mayor McHottie, Jennifer’s boyfriend (who actually does have Scottish blood).
   I could always be McJ.
   Oh, what confuses me about all of this is that McSweaty is the nickname for a character called Dr Mark Sloan, but when I Googled the character from the show, he looks nothing like Dick van Dyke. Anyone care to explain? Is this a cross-over character from Diagnosis: Murder, and will Drs Ben Casey, Jim Kildare and Adam Bricker be the next additions to the cast?
   I, for one, am glad that Bones is Emily Deschanel, who is more pleasant on the eyes than DeForest Kelley, but these Star Trek spinoffs are too tough for me to follow.