kyynelnesteistä

Kyynelnesteet, often referred to as tears, are a vital component of eye health. Produced by the lacrimal glands, these fluid secretions serve multiple crucial functions for the ocular surface. Their primary role is lubrication, ensuring that the cornea and conjunctiva remain moist and preventing them from drying out, which would cause discomfort and potentially damage.

Beyond lubrication, tears act as a cleaning agent. They wash away small particles of dust, debris, and irritants that may enter the eye, thus protecting the delicate structures from harm. Tears also contain antibodies and enzymes, such as lysozyme, that possess antimicrobial properties, helping to fight off infections and maintain a sterile environment within the eye.

The composition of tears is complex, consisting primarily of water, but also containing electrolytes, proteins, lipids, and other substances. This balanced composition is essential for maintaining the health of the tear film, a thin, three-layered membrane that covers the eye's surface. Disruptions to this film, whether due to insufficient production or poor quality, can lead to conditions like dry eye disease.

Emotional crying, distinct from basal or reflex tearing, is a unique human response. While the exact physiological purpose of emotional crying is still debated, it is believed to play a role in stress reduction and social signaling. Regardless of the trigger, the physical act of crying involves the overflow of tears from the lacrimal puncta into the nasolacrimal duct, which drains into the nasal cavity, often resulting in a runny nose.