Final answer:
The tear film is made up of three layers: the outer lipid layer, the middle aqueous layer, and the inner mucous or mucin layer. Each layer has a specific function and is produced by different glands and cells in the eye to maintain eye health.
Step-by-step explanation:
The area that makes up each layer of the tear film on the eye can be broken down into three distinct layers. These layers are essential for protecting and nourishing the eye. The outermost layer is the lipid layer, which prevents evaporation of the underlying layers. It is produced by the Meibomian glands located on the edges of the eyelids. The middle layer is the aqueous layer, which is the thickest layer made mostly of water, and provides moisture, oxygen, and important nutrients to the cornea. It is secreted by the lacrimal glands. The innermost layer is the mucous or mucin layer, secreted by goblet cells in the conjunctiva, and helps to spread the aqueous layer over the surface of the eye and adhere the tear film to the ocular surface.