conjunctiva

The conjunctiva is a thin, transparent mucous membrane that lines the inside of the eyelids and covers the white part of the eye (sclera), playing a crucial role in eye protection and lubrication.

Anatomy of the Conjunctiva

It is divided into three main parts:

1. Palpebral Conjunctiva

   • Lines the inner surface of the eyelids (upper and lower).
   • Highly vascular and tightly adherent to the tarsal plate.

2. Bulbar Conjunctiva

   • Covers the anterior part of the sclera up to the limbus (where the cornea begins).
   • Loosely attached to the underlying sclera.
   • Transparent, so the white sclera is visible underneath.

3. Fornical Conjunctiva (Conjunctival Fornix)

   • The junction where the palpebral and bulbar conjunctivae meet.
   • Forms a loose fold, allowing free movement of the eye.
   • Superior and inferior fornices are present.

Histology

• Composed of non-keratinized stratified columnar epithelium (can be cuboidal in some areas) with goblet cells, especially in the fornices.
• Goblet cells secrete mucin, which contributes to the tear film and keeps the eye moist.
• The underlying substantia propria contains blood vessels, lymphatics, and immune cells.

Functions

• Protects the eye by trapping debris and microorganisms.
• Produces mucus and contributes to the tear film.
• Provides immune surveillance with lymphoid tissue (conjunctival-associated lymphoid tissue – CALT).

Let me know if you want a labeled diagram or further detail on conditions like conjunctivitis or pterygium.