The secretion of tears is primarily accomplished by several structures in the eye.
Tear Production and Its Sources
Here’s a breakdown of the main contributors to tear production:
- The Main Lacrimal Glands: These are the primary producers of the aqueous tear layer, which is the watery part of tears. They are responsible for the bulk of tear volume needed for eye lubrication and cleansing. [2]
- Goblet Cells in the Conjunctiva: These cells, located within the conjunctiva (the thin membrane covering the white part of the eye), secrete a small amount of the aqueous tear layer. [2]
- Accessory Lacrimal Glands: These smaller glands also contribute to the aqueous layer, supplementing the work of the main lacrimal glands. [2]
How Tears Work
Tears aren’t just water; they are a complex mixture. Here is a breakdown of components:
- Aqueous Layer: The primary component is the watery layer that keeps the eye moist.
- Mucin Layer: The mucin layer, secreted by goblet cells, allows the tear film to spread evenly over the eye.
- Lipid Layer: The lipid layer prevents the tears from evaporating too quickly, produced by the meibomian glands in the eyelids.
Why Tears Are Important
Tears serve several crucial functions:
- Lubrication: They keep the surface of the eye moist, preventing dryness and discomfort.
- Protection: They wash away debris, dust, and microorganisms.
- Nutrition: They provide essential nutrients to the cornea (the clear front part of the eye).
- Smooth Surface: They ensure the cornea has a smooth surface for clear vision.
Tear Drainage
After tears are produced, they are not constantly overflowing, as they are drained by:
- Lacrimal Puncta: These small openings are located in the inner corners of the eyelids. [2]
- Nasolacrimal Duct: This duct carries the tears into the nasal cavity.
| Tear Producing Structure | Amount of Aqueous Production |
|---|---|
| Main Lacrimal Glands | Most |
| Goblet Cells of Conjunctiva | Small Amount |
| Accessory Lacrimal Glands | Small Amount |
