What makes us shed tears

Our eyes have tear or lacrimal glands located at the outer corner of our eye behind the upper eyelid. When we blink, a salty solution is released that washes the eyes and is drained into the tear duct in the corner of the eye. It has been observed that during happiness or sadness, there is excess blood flows to the face or increased pressure and the upper eyelid squeezes the lacrimal gland. When these causes excessive build up, it comes out in the form of tears in our eyes.