tårkanalsystemet

The tårkanalsystemet, or lacrimal system, is a complex network of structures within the eye and surrounding facial bones responsible for the production, distribution, and drainage of tears. Its primary function is to keep the ocular surface lubricated and clean, protecting it from pathogens and debris. Tears are produced by the lacrimal glands, which are located above the outer corner of each eye. These glands secrete a fluid that spreads across the cornea and conjunctiva with each blink, forming a protective tear film.

This tear film consists of three layers: an outer lipid layer produced by meibomian glands in the eyelids, a middle aqueous layer from the lacrimal glands, and an inner mucin layer from goblet cells in the conjunctiva. This stratification ensures optimal hydration and smooth vision.

The drainage of tears begins at small openings called puncta, located on the inner edge of both the upper and lower eyelids. From the puncta, tears flow into tiny tubes called canaliculi, which lead to a larger sac called the lacrimal sac. The lacrimal sac is situated in a groove on the side of the nose. Finally, the tears descend through the nasolacrimal duct, which empties into the nasal cavity. This is why crying often results in a runny nose. Disruptions to any part of this system can lead to conditions like dry eye or excessive tearing.