CRISTINA EXPERIENCES SEVERE POST-TRAUMATIC STRESS IN THE OR -- MID-SURGERY -- ON ABC'S "GREY'S ANATOMY"

James Tupper ("Men in Trees") Guest Stars

"Shock to the System" -- After weeks of concealing the fact she was pregnant and miscarried, Meredith at last tells Derek and is finally cleared to return to her surgical duties in the wake of the hospital shooting spree; Cristina experiences post-traumatic stress disorder in the midst of an operation; and Bailey refuses to let Alex operate until he agrees to have the bullet in his chest removed, on "Grey's Anatomy," THURSDAY, SEPTEMBER 30 (9:00-10:01 p.m., ET) on the ABC Television Network.

"Grey's Anatomy" stars Ellen Pompeo as Meredith Grey, Patrick Dempsey as Derek Shepherd, Sandra Oh as Cristina Yang, Justin Chambers as Alex Karev, Chandra Wilson as Miranda Bailey, James Pickens, Jr. as Richard Webber, Sara Ramirez as Callie Torres, Eric Dane as Mark Sloan, Chyler Leigh as Lexie Grey, Kevin McKidd as Owen Hunt, Jessica Capshaw as Arizona Robbins, Kim Raver as Teddy Altman, Jesse Williams as Jackson Avery and Sarah Drew as April Kepner.

Guest cast includes James Tupper as Andrew Perkins, Ashley Crow as Linda, John Walcutt as Paul, Camille Chen as Kerry, Walter Perez as Russ, Chuck Hittinger as Mitch and Eric James Ramey as Warren.

"Shock to the System" was written by William Harper and directed by Tom Verica.

"Grey's Anatomy" is broadcasted in 720 Progressive (720P), ABC's selected HTV format, with 5.1-channel surround sound. This program carries a TV-14, L,V parental guideline.

For more information on "Grey's Anatomy" please visit ABC.com.