Tears: Salty Liquid?
Tears have a similar salt concentration to blood plasma. This is because they share the same origin, with tear glands filtering blood to produce tears.
Salt's Protective Role
The salt in tears acts as an antiseptic. It helps to kill bacteria, protecting the eyes from infections and aiding in the maintenance of ocular health.
Osmotic Balance Maintenance
The osmotic balance of tears is crucial. It prevents dehydration of ocular tissues by controlling water flow across the cell membrane, keeping cells healthy.
Emotional Tears' Secret
Emotional tears contain more protein-based hormones than reflex tears, which are triggered by irritants. This difference hints at emotional tears' role in stress relief.
Tears: Healing Mechanism
Crying releases manganese and other stress hormones, potentially regulating mood and stress levels. This suggests a healing aspect beyond the simple removal of irritants.
Salt in Evolution
Salty tears may have evolved to enhance visibility in salty seawater or to manage the sunlight glare on water, providing a survival advantage to early humans.
Crying's Complex Chemistry
Tears are not just salty but are a complex solution containing oils, enzymes, and antibodies. Their intricate composition reflects the eye's multifaceted protective requirements.