What does the conjunctiva refer to?

The conjunctiva is a vital structure of the eye that encompasses both the mucous membrane lining the eyelids and covering the anterior portion of the sclera, which is the white part of the eye. This membrane plays several important roles in eye health, including providing lubrication through the secretion of mucus and tears, and serving as a barrier against pathogens and irritants.

Understanding that the conjunctiva lines the eyelids helps clarify its role in protecting the eye by contributing to the tear film and maintaining moisture. Additionally, its presence over the sclera indicates its function in providing a smooth surface for movement of the eyelids, thereby facilitating blinking. Therefore, recognizing that the conjunctiva consists of both these components explains why the correct answer encompasses both options related to its anatomy and function.