The seventh season of Grey's Anatomy commenced last night. Click here for our thorough season premiere review, then get ready for the first promo for next week below.

Meredith tells Derek about the miscarriage at last and is cleared to return to the OR, while Cristina experiences PTSD at a bad time, and Bailey refuses to let Alex operate.

The episode stills we posted a few moments ago hint at a very emotional episode for all of the above characters. Here's your first glimpse of "Shock to the System" ...

[video url="http://www.tvfanatic.com/videos/shock-to-the-system-promo/" title="Shock to the System Promo"] [/video]

Steve Marsi is the Managing Editor of TV Fanatic. Follow him on Google+ or email him here.