Why do we cry? Scientists have been trying to answer this question for centuries. In 1662, Danish scientist Niels Stensen discovered that tears originate in the lacrimal gland. We have three distinct types of tears: Basal tears. Reflex tears. Emotional tears. Basal tears: In healthy mammalian eyes, the cornea is continually kept wet and nourished by basal tears. They lubricate the eye, and help to keep it clear of dust. Reflex tears: results from irritation of the eye by foreign particles, or from the presence of irritant substances such as onion vapors, perfumes and other fragrances, tear gas, or pepper spray in the eye's environment, including the cornea, conjunctiva, or nasal mucosa, which trigger TRP channels in the ophthalmic nerve. Emotional tears: Most researchers believe that emotional tears—triggered by strong feelings such as joy and sadness—are unique to humans. While there is a lot of crying research currently underway...