Ciliary body

What is the ciliary body?

An inner eye structure located at the border between the choroid and the iris.

What is the color of the ciliary body and why?

Brown due to melanin pigment.

What structures are included in the ciliary body?

Ciliary muscle, ciliary processes, ciliary vessels, ciliary epithelia.

What is the shape of the ciliary body cross-section?

Triangular.

What is the width of the ciliary body?

Varying from 5.5 to 6.5 mm.

What is the ora serrata?

Crenated or scalloped periphery of the ciliary body continuous with the choroid and retina.

How many dentate processes are there approximately per eye?

20 to 30 dentate processes.

What are the two parts of the triangular ciliary body?

Pars plicata (anterior part) and pars plana (posterior part).

What is the role of ciliary processes?

Attach to the lens via fibrous zonular fibers and participate in accommodation reflex.

What are the dimensions of a ciliary process?

Approximately 2 mm in length, 0.5 mm in width, and 1 mm in height.

What is the difference between pars plicata and pars plana?

Pars plicata is finger-like and anterior, while pars plana is flat and posterior.

What is the role of the non-pigmented epithelium (NPE)?

Produces aqueous humor and extends from iris root to ora serrata.

What type of cells compose the pigmented epithelium?

Cells with large pigment granules that are metabolically active.

What does ciliary stroma consist of?

Bundles of loose connective tissue, blood vessels, nerves, and ciliary muscle.

What is the primary function of the ciliary muscle?

To change the shape of the lens for accommodation.

What are the three parts of the ciliary muscle?

Outer longitudinal (Brücke's muscle), middle oblique, inner circular (Müller's muscle).

What effect does contraction of the ciliary muscle have on accommodation?

Increases the convexity of the lens, aiding in accommodation.

How is the ciliary muscle innervated?

By parasympathetic postganglionic fibers from the oculomotor nerve.

What is the role of zonular fibers?

Connect the ciliary body to the lens.

What is the function of the supraciliary lamina?

Acts as a potential space helping aqueous humor to exit via an unconventional pathway.

What is the composition of the ciliary epithelium?

Two layers: pigmented and non-pigmented.

What connects the internal limiting membrane to the ciliary body?

The basal lamina of non-pigmented epithelium.

Where does the ciliary stroma continue to?

Anteriorly with iris stroma and posteriorly with choroidal stroma.

How do sympathetic fibers interact with the ciliary muscle?

They synapse in the superior cervical ganglion and likely have an inhibitory effect.

What is the distance between the equator of the lens and the ciliary body?

Approximately 0.5 mm.

What is the primary role of the ciliary processes in the eye?

To assist in the accommodation reflex by attaching to the lens.

What are dentate processes?

Teeth-like extensions of neurosensory retina into pars plana.

How many ciliary processes are there approximately?

Around 70 to 80.

What happens to zonular fibers during ciliary muscle contraction?

They loosen, allowing the lens to become more convex.

What are some characteristics of the ciliary muscle?

Non-striated, smooth muscle situated mainly in the anterior two-thirds of the ciliary body.

What is the relationship between the ciliary body and the uveal tract?

The ciliary body, iris, and choroid collectively comprise the uveal tract.

What type of muscle fibers predominates in the ciliary muscle?

Smooth muscle fibers.

What happens to the non-pigmented epithelium of the ciliary body with age?

Cells become smaller and decrease melanin granules.

Which muscle of the eye works with the ciliary muscle in controlling the pupil size?

Dilatator pupillae and sphincter pupillae muscles.

What determines the color and pigmentation of the ciliary body?

Melanin granules in the epithelial cells.

What is the structure continuous with the inner limiting membrane of the retina?

The internal limiting membrane secreted by the non-pigmented epithelium.

Where does the ciliary muscle secretion reach?

To the ciliary body and lens.

Describe the shape of ciliary muscle bundles.

The inner circular portion acts as a sphincter, circular in shape.

How does the ciliary body assist in vision?

By adjusting the lens shape for focus through accommodation.

What are the major functions of the ciliary body?

Accommodation, secretion of aqueous humor, and connection to the lens.

How do dentate processes appear on the ora serrata?

As forward extensions into the retina, well defined nasally and less so temporally.

What is the significance of melanin in the ciliary body?

It contributes to the brown color and protects the eye from UV radiation.