GREY'S ANATOMY - "Heart-Shaped Box" - The doctors become nostalgic when George O'Malley's mother, Louise, returns to Seattle Grace for medical help after a botched surgery at a neighboring hospital; the residents are inspired by a medical miracle when they witness a harvested heart that continues to beat outside the body; a new pediatric fellow excites Arizona and makes Alex feel threatened; Jackson lets his suspicions about Mark and Lexie interfere with his work; and Henry and Teddy have their first marital fight when he expresses interest in pursuing medical school, on "Grey's Anatomy," THURSDAY, NOVEMBER 3 (9:00-10:02 p.m., ET) on the ABC Television Network. (ABC/RANDY HOLMES) SCOTT FOLEY, KIM RAVER