What's normal anxiety -- and what's an anxiety disorder?

Everyone gets anxious at times, but how can you tell when worrying and fear crosses the line and needs attention? Dr. Jen Gunter introduces a special part of the brain called the amygdala and shares the science behind your brain's threat-detection system, what causes it to malfunction and the most effective ways of treating an anxiety disorder. Want to hear more from Dr. Gunter? Check out her podcast Body Stuff, from the TED Audio Collective.