The Welsh side scored six tries, claiming a bonus point in the process, while fly-half Henson finished with 24 points.
Ryan had been confident about his team's ability to withstand wholesale changes, but the Ospreys emphatically mocked his theory as they ran out 49-19 winners.
"Intensity was the core area," said Ryan. "They won the physical collisions and played off the back of that with a world-class number nine (Justin Marshall).
"We didn't turn up with enough intensity to make it an even contest, which was disappointing.
"Coming to this type of environment, you will receive an extremely physical game, and it was a great opportunity for some people to learn some lessons.
"But we have lost one game, and we have two to come at home in this tournament. I don't think it is a competition that is beyond us just because of tonight."
Centre Sonny Parker claimed a quickfire try double just after half-time, securing a bonus point for the Ospreys following opening touchdowns by wing Shane Williams and hooker Barry Williams.
Henson's haul included a try, while Marshall galloped over from 40 metres to confirm the rout.
The only worrying note for a rampant Ospreys side came when number eight Ryan Jones limped off midway through the second period nursing what appeared to be a knee problem.
Wales international Jones, a 2005 Lions tourist, missed the whole of last season through a shoulder injury, and he is an integral part of national coach Gareth Jenkins' autumn Test plans.
Gloucester managed a Peter Richards try and 14 points from Ludovic Mercier, but they were hopelessly outclassed in all key departments as their hopes of reaching the Millennium Stadium semi-finals next March spectacularly nose-dived.
"It was a powerful performance by us - we responded well from last week (a 43-7 Magners League defeat against Ulster)," said Ospreys coach Lyn Jones.
"We looked like a team, and we created space that meant individual flair came through. It was a complete 100% turnaround."