Teacher's Violent Meltdown Caught on Tape

More and more videos are popping up on YouTube of teachers flipping out in front of their classes, as students grab the incidents on their cell phones.

And one such freak-out in McGavock High School in Nashville Friday was so extreme, officials are saying Brian Wood was actually having a nervous breakdown as he led an 11th grade algebra class, reports CBS News Correspondent Jeff Glor.

At the start, Wood, who's been a teacher for 21 years, is just screaming at the students as they laugh back at him in what Glor says seemed like harmless play, but it evolves, and Wood is seen throwing desks, even smashing a window with one of them.

It got so bad students ran from the classroom, Glor says. McGavock's principal, Robbin Wall, admits it was lucky no one was hurt.

Wood's sister, Leanne Smith, said in a news conference Monday her brother regrets his actions. "He expressed his passion and love for teaching and concern for his students," she said.

Although Smith didn't say exactly what caused his erratic actions, she pointed to the students' disruptive behavior in the video, and hinted disrespect in the classroom is a problem across the country, saying, "The lack of respect for authority in our society's classrooms across the nation is one of the many consequences of the way public school teachers are forced to deal with their classrooms today."

Wood, a father of five, has been placed on administrative leave as he continues treatment at a nearby hospital.

In his report, Glor also showed bits of other videos of teachers losing it, including one actually dragging and hitting a student: