Ciliary Body Anatomy
Anteriorly, the ciliary stroma is continuous with the _____.
connective tissue of iris
What is separated by the ciliary stroma?
epithelium and ciliary muscle
The ciliary body is _____ to the sclera, ____ to the choroid, and ______ to the iris.
internal to sclera (K) anterior to choroid (M) posterior to iris (E)
The pars plana lies adjacent what structure?
ora serrata → retina
Between each dentate process is a ____.
oral bay
What portion of the ciliary body is made up of the pars plana?
posterior 2/3 of ciliary body
What is the function of the ciliary stroma?
provide passage for the BVs and nerves
What are meridional folds?
radially aligned elevation elevation of the peripheral retina lined up with the dentate processes begin in the ora serrata and run posteriorly and perpendiculary to the ora seratta may be associated with retinal breaks (found in 20% of autopsies)
The supraciliaris is continuous with the _____.
suprachoroidal space
Is the ciliary body longer temporally or nasally?
temporally (longest inferotemporally)
What is the origin of the of the circular muscle fibers?
scleral spur no insertion because the run circumferentially forming a sphincter
What is the origin of the longitudinal or meridional layer?
scleral supr and part of trabecular meshwork
What is a plicae circulares?
smaller subsidiary folds to the larger folds of the Pars Plicata
What is the supraciliaris?
a supraciliary space - potential space
What portion of the ciliary body is made up of the Pars Plicata?
anterior 1/3 of ciliary body
Is the pars plana thicker anteriorly or posteriorly?
anteriorly
What bathes the face of ciliary body?
aqueous in the anterior champer
Where are the Pars Plicata and the Pars Plana in relation to the Lens and the Ora Serrata?
border between orange and brown = ora serrata brown = pars plana white section = pars plicata lens would sit behind the iris and pupil
The ciliary body is an anterior continuation of the ____.
choroid
What is the insertion of the longitudinal or meridional layer?
choroid and sclera to the equator
Which is darker, the choroid or the ciliary body?
ciliary body
How long is the ciliary body nasally?
4.6 - 5.2 mm (surgically: 6 mm)
Describe the ciliary epithelium?
- double epithelial layer - cells oriented apex to apex - pigmented epithelium - non-pigmented epithelium
What are the 4 primary functions of the ciliary body?
1. aqueous production and outflow 2. accommodation 3. vitreous production 4. blood/aqueous barrier
What are the three parts of the ciliary muscle?
1. longitudinal or meridional - outermost layer 2. oblique or radial - intermediate muscle mass 3. circular muscle fibers - deepest muscle mass
What are the general characteristics of the ciliary muscle?
1. similar to other smooth muscle in the body 2. fibers covered by BM 3. CT between fibers contain: - nerves - collagen fibers - melanocytes - ground substance - non-fenestrated BVs
What are the four layers of the ciliary body?
1. supraciliaris 2. ciliary muscle 3. stroma 4. ciliary epithelium
How wide is the pars plana?
3.5 - 4 mm
How long is the ciliary body temporally?
5.6 - 6.3 mm (surgically: 7 mm)
What are the Pars Plicata and Pars Plana? Where are they in relation to each other?
Pars Plicata: folded and anterior portion of the ciliary body Pars Plana: smooth portion of the ciliary body posterior to the Pars Plicata
What is found within the ciliary stroma?
fibroblasts melanocytes lymph mast cells loose collagen fenestrated blood vessels
What connects the supraciliaris to the sclera?
fine collagen fibrils
How do the ciliary processes of the Pars Plicata affect the production of aqueous?
folds in the inner surface increases the surface area for aqueous production
Where is the ciliary stroma thickest?
in the pars plicata
What structures are matted down along the inner surface of the Pars Plana?
lens zonules
What travesl through the supraciliaris?
nerves blood vessels
What part of the ciliary body is continuous with the sensory retina posteriorly?
non-pigmented epithelium
What is the origin and insertion of the oblique or radial muscle mass?
origin → scleral spur insertion → connective tissue of the folds of pars plicata
Describe the innervation to the ciliary muscle.
parasympathetic M3 muscarinic receptors - innervation activate muscle contraction sympathetic ß2 adrenergic receptors - innervation relaxes the muscle
What structure gives the Pars Plana a striated appearance? Where do they come from?
striae ciliaris: strips extending from the dentate processes
Posteriorly, the ciliary stroma is continuous with the ____.
stroma of choroid collagenous and elastic layer of Bruch's
The posterior Pars Plana attaches to what structure?
the vitreous base → extemds 2 mm over posterior Pars Plana
What is the shape of the ciliary body?
triangular
True or false. The ciliary body is the most vascularized tissue of the eye.
true
How is the ciliary muscle attached to the sclera?
via the scleral spur
How is the lens attached to the ciliary body?
via zonules
The pars plana produces some components of _____.
vitreous
When does a meridional fold become a meridional complex?
when it extends into a striae ciliaris (not as common as meridonial folds)
The Pars Plicata serves as the attachment site for _____.
zonules
