The lacrimal system is responsible for the production and drainage of tears. It includes the lacrimal glands, which produce tears to keep the eyes moist and protect them from irritants. Tears also contain enzymes that help fight infections. Once tears are produced, they flow across the surface of the eye and drain through small openings called puncta located in the inner corners of the eyelids. From there, tears travel through the lacrimal canals into the lacrimal sac and then down the nasolacrimal duct into the nose, which is why crying can make your nose run.