The upper half of a sagittal section through the front of the eyeball. (Label for 'Conjunctiva' visible at center-left.)
Horizontal section of the eyeball. (Conjunctiva labeled at upper left.)
|lacrimal artery, anterior ciliary arteries|
The conjunctiva lines the inside of the eyelids and covers the sclera (white part of the eye). It is composed of non-keratinized, stratified columnar epithelium with goblet cells, and also stratified columnar epithelium.
The conjunctiva helps lubricate the eye by producing mucus and tears, although a smaller volume of tears than the lacrimal gland. It also contributes to immune surveillance and helps to prevent the entrance of microbes into the eye.
The conjunctiva is typically divided into three parts:
|Palpebral or tarsal conjunctiva||Lines the eyelids.|
|Bulbar or ocular conjunctiva||Covers the eyeball, over the anterior sclera. This region of the conjunctiva is tightly bound to the underlying sclera by Tenon's capsule and moves with the eyeball movements.|
|Fornix conjunctiva||Forms the junction between the bulbar and palpebral conjunctivas. It is loose and flexible, allowing the free movement of the lids and eyeball.|
Sensory innervation of the conjunctiva is divided into four parts:
|Lateral||Lacrimal nerve (with contribution from zygomaticofacial nerve)|
|Circumcorneal||Long ciliary nerves|
The conjunctiva consists of non-keratinized, both stratified squamous and stratified columnar epithelium, with interspersed goblet cells. The epithelial layer contains blood vessels, fibrous tissue, and lymphatic channels. Accessory lacrimal glands in the conjunctiva constantly produce the aqueous portion of tears. Additional cells present in the conjunctival epithelium include melanocytes, T and B cell lymphocytes.
Diseases and disorders
Disorders of the conjunctiva and cornea are a common source of eye complaints.
The conjunctiva can be affected by tumors which can be benign, pre-malignant or malignant.
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