Ciliary Body Flashcards
What is the ciliary body continuous with?
Iris
What are the 2 portions of the ciliary body?
Which is anterior? Posterior?
Pars plicata (anterior 1/3)
Pars plana (posterior 2/3)
Describe the structure of the pars plicata? What does it contain?
Anterior 1/3 of ciliary body
Contains ciliary process that produces aqueous
Not smooth, plicated
Describe the structure of the pars plana? Where does it extend to?
Posterior 2/3 of ciliary body
Extends back to ora serrata of retina
What are the 4 functions of the ciliary body?
Accommodation
Aqueous production
Zonule production
Vitreous production
On what side are dentate processes more obvious?
Nasal is more obvious compared to temporal side
Which portion of the ciliary body is best in inject needle into? Why is this?
Pars plana
Has lower blood supply
How far is the pars plana behind the limbus? Does this vary?
3 to 4mm
Yes, for high myopes and hyperopes
Describe the orientation of the apex, anterior, posterior corners, and middle of the ciliary body.
Triangular base is more anterior
Anterior corner at scleral spur
Middle is at iris root
Posterior is next to posterior chamber
Apex at ora serrata
What region will the lens be placed if an issue occurs during cataract surgery?
Ciliary sulcus
Where do the zonules attach to? How do they aid in accommodation?
Attach to pars plana and lens
Hold lens in place and provide tension based on ciliary body to aid in accommodation
What are the 4 layers of the ciliary body from outer to inner?
Supraciliaris
Ciliary Muscle
Ciliary Stroma
Two layers of epithelium
What are the functions of collagen bands in the supraciliaris? What other 2 structures are located in the supraciliaris?
Collagen bands allows CB to slide and move
Fibroblasts and pigmented melanocytes
Fluid under abnormal conditions
What is on the posterior side of the supraciliary space?
Lamina fusca (sclera)
What are the 3 ciliary muscles?
Longitudinal muscle
Radial muscle
Circular muscle
Describe the 2 layers of epithelium. Which is outer/inner, which is pigmented/non pigmented? What are each continuous with?
Pigmented ciliary epithelium (outer)- continuous with anterior iris epithelium
Nonpigmented ciliary epithelium (inner)- continuous with posterior iris epithelium
What is the orientation of the two layers of the CB epithelium?
Apex to Apex
Describe ciliary body detachment (effusion).
Separation of ciliary body and sclera in supraciliaris space, cause when pressure gets low, fluid enters.
What is the sensory innervation to the ciliary body from?
Nasociliary branch of V
What is the pathway of sympathetic innervation in the ciliary body?
Superior cervical ganglion
LPCN
Blood vessels (to control tonus)
What is the pathway of parasympathetic innervation in the ciliary body?
Ciliary ganglion
SPCN
Ciliary muscle (accommodation)
Describe the vascular supply to the CB.
Major Circle of Iris- Branches go posterior to CB
Venous return mostly through vortex veins
Terminate at fenestrated capillaries
What happens to the non pigmented epithelium at the ora serrata?
Becomes multi layered
Describe orientation the longitudinal ciliary muscle.
Adjacent to the supraciliaris
Parallel to the sclera
Long narrow “V”- apex in choroid, base at spur
Where does the origin and insertion of the longitudinal ciliary muscle occur?
Tendon of origin inserts into spur and TM
Insertion into choroid via stellate-shaped terminations or “muscle stars.”
Describe orientation the radial ciliary muscle.
Beneath (deep) the longitudinal muscle
Wider, shorter interdigitating “Vs”
Transition to circular fibers
Outer to ciliary
Where does the origin and insertion of the radial ciliary muscle occur?
Origin at spur
Insertion into connective tissue near the base of ciliary processes
Describe the orientation of the circular ciliary muscle (muller’s annular muscle).
Innermost
Circular muscle bundle with sphincter-like action
Describe the orientation and histology of the ciliary stroma. What does it form? What is it continuous with?
Loose connective tissue lying between the muscle and the epithelial layers
Forms core of the ciliary processes
Continuous with the connective tissue separating muscle bundles
What is the ciliary storma continuous with anteriorly and posteriorly?
Anteriorly – continuous with iris stroma
Posteriorly – thins at pars plana and becomes continuous with the choroidal stroma
What major circle is located in the stroma?
Major anterior circle is in stroma, anterior to the circular muscle and near the iris root
Describe the capillaries within the ciliary stroma. Where are they mainly located?
Large and fenestrated (leaky)
Mainly near the ciliary processes where aqueous is made
Describe the outer layer of the ciliary epithelium. Histology, location, continuity, communication?
Next to stroma
Pigmented
Cuboidal
Joined by desmosomes and gap junction
Continuous with anterior iris epithelium and RPE
Describe the inner layer of the ciliary epithelium. Histology, location, continuity, communication?
Nonpigmented
Columnar in the pars plana and cuboidal in the pars plicata
Near apices: desmosomes, gap junctions, tight junctions
Blood– Eye Barrier
Continuous with posterior iris epithelium and sensory retina
ACTIVELY secretes aqueous humor
