The difference between CD, and UC?

I always try to read up on as much as I can on my illness(UC).  But it seems every site I go to bunches the 2 diseases together.

I was curious on how many famous people had UC, so I looked it up, but 80% of the people mentioned had CD, not UC.

They seem to make CD sound more serious for some reason.(using terms life threatening ect)

Can someone explain the largest difference in the 2?

 

Crohn's also involves all of the layers of the gut wall, while UC only involes the inner, mucosal lining of the colon. Therefore, Crohn's commonly causes fistulas, blockage from scar tissue, and less commonly perforation. These can all be life-threatening. UC, on the other hand, rarely causes life-threatening conditions (although perforation can occur in certain circumstances when the disease is poorly controlled.) But statistically, the life expectancy for UC is no different than the general population.