Why do we cry tears?

tears are produced by the lacrimal or tear glands located under the upper eyelid. these glands constantly produces a small amount of tears that keep the eye moist. tears contain an enzyme lysozyme that protects the eye from bacteria. The tear gland produces more tears when the eyes are irritated, the flushing action of the tears keeps irritants and aerosols from entering the eye and causing irritation. these extra tears are called reflex or irritant tears. And when something makes you happy or sad, your brain centres stimulate the tear glands to produce emotional tears. when these are produces in large quantities they overflow your lower eyelid and run down you cheeks. emotional tears differ in their chemical content from those caused by irritants. emotional tears contain more protein and it is believed that emotional crying is an eliminative process which dispenses off toxic substances from the body.

all species that have eyes produce tears. you wil see it if u have a dog. there is usually a small amount of tears leaked near the eye.