Human tears contain a complex mixture of chemicals, with lysozyme being a prominent antimicrobial factor.
Tears are more than just salty water; they are a crucial component of eye health. The tear film consists of three layers: a lipid layer, an aqueous layer, and a mucin layer. The aqueous layer, the thickest, contains various proteins and electrolytes, including chemicals that fight infection.
Here's a breakdown of some key chemicals found in human tears:
- Lysozyme: This enzyme is a powerful antimicrobial agent that breaks down bacterial cell walls, protecting the eye from infection. It's one of the most abundant proteins in tears.
- Lactoferrin: Another antimicrobial protein, lactoferrin binds iron, depriving bacteria of this essential nutrient for growth.
- Transferrin: Similar to lactoferrin, transferrin also binds iron, contributing to the antimicrobial properties of tears.
- Immunoglobulins (IgA, IgG, IgE): These antibodies help neutralize pathogens and prevent them from adhering to the ocular surface. IgA is the most prevalent immunoglobulin in tears.
- Electrolytes: Sodium chloride (salt), potassium, and other electrolytes maintain the proper osmotic balance of tears.
- Glucose: A small amount of glucose is present in tears to provide nourishment to the corneal epithelium.
- Lipids: While the lipid layer primarily consists of fats, some lipids are also found within the aqueous layer.
- Other proteins and enzymes: Ceruloplasmin, complement components, glycoproteins, and anti-proteinases are also present, each playing specific roles in maintaining eye health and defense.
In summary, while many chemicals are present, lysozyme stands out as a key antimicrobial factor in human tears, significantly contributing to the eye's defense against infection.
