Pars plicata

Pars plicata is a part of the ciliary body, an important structure in the eye. It is located in the anterior part of the ciliary body, and is characterized by its numerous radial folds, or plicae. These folds are responsible for the name "pars plicata", which is derived from the Latin words for "folded part".

Anatomy

The pars plicata is approximately 2 mm wide and is the anterior part of the ciliary body. It is covered by a double layer of epithelial cells, the outer pigmented and the inner non-pigmented. The non-pigmented epithelial cells are responsible for the production of aqueous humor, a clear fluid that fills the anterior chamber of the eye.

The pars plicata is also characterized by approximately 70-80 radially oriented ciliary processes. These processes are small protrusions that extend into the posterior chamber of the eye. They are covered by the ciliary epithelium and contain blood vessels that provide nutrients to the eye.

Function

The primary function of the pars plicata is the production of aqueous humor. This fluid is essential for maintaining the intraocular pressure and providing nutrients to the cornea and lens.

The ciliary processes of the pars plicata also play a role in the accommodation of the lens. They are attached to the lens by the zonule fibers, and their contraction and relaxation changes the shape of the lens, allowing the eye to focus on objects at different distances.

Clinical significance

Abnormalities in the pars plicata can lead to various eye disorders. For example, overproduction or impaired drainage of the aqueous humor can result in glaucoma, a condition characterized by increased intraocular pressure and potential vision loss. Inflammation of the pars plicata, known as pars plicataitis, can also occur, often as a part of uveitis, an inflammation of the uveal tract.