It begs the questions how does it all work, and what triggers our waterworks when we are both sad - and happy? Get your tissues at the ready, it’s all about tears this week. Crying can be ...

With reflex tears, nerves in the eyes signal to the brainstem that ... In fact, this is how scientists study crying: They show people a sad clip from a film and see if it turns on the waterworks.

Anyone who has ever noticed tears in their cat's eyes has probably wondered ... So if cats don’t cry, how do you know when they’re sad? There are definitely signs to look for if you think ...