nogueira ko'ed in sparring multiple times

Knocked out...cold? What does MMA sparring usually entail? Is there headgear? Do they compartmentalize all the different aspects of the game (ie work on judo by itself, then boxing by itself, etc.) or treat it as a practice-run of a real match with everything mixed in?

 

All camps run things differently usually when they practice a real fight its kinda more timing then anything because its hard to spar hard and still do grappling with shin pads and head gear on.