When we cry, why do we have tears?

When we cry we put pressure into our heads. This pressure causes a backup of tears into our eyes from our noses. We also increase our blood flow to our face and eyes, which causes an increase in the amount of tears. These two things cause our eyes to be over filled with tears. And because we have too many tears to fit into our eyes, they flow down our cheeks as we cry.


Why do people sleep?Ask a Doctor:Why do we throw up?