Ciliary Body

what defines the anterior chamber

anterior chamber is located within the cornea and iris

what defines the posterior chamber

posterior chamber is located within the iris and the anterior surface of the vitreous

is the ciliary body located 360 degrees

yes

what is the pars plicata

• the ciliary processes and valleys

• ciliary processes: tissue crests

• valleys: regions between the crests

what is the pars plicata involved in

aqueous humor production and assists in accommodation

what is the pars plana

the flatter portion of the ciliary body

where does the pars plana extend

extends from ora serrata to ciliary processes

what is the ora serrata

the transition zone/where the retina terminates

what is the supraciliaris

it’s located interior to the sclera and external to pars plicata

what is the supraciliaris composed of

• pigmented ribbon like layers of loose connective tissue

• collagen

• melanocytes

• fibroblasts

what is the purpose of the supraciliaris

• serves as an intermediate

• creates a potential space

• fluid can drain here

what is the muscle that is located in the ciliary muscle like

• reticulum of smooth muscle with interweaving layer to layer

• sphincter-like contraction of ciliary muscle

what are the junctions that make up the ciliary muscle

gap and tight that allow it to act as a syncytium

where does the longitudinal muscle layer start

sclera spur

where does the longitudinal muscle layer terminate

suprachoroid

where is the sclera spur located

anterior to the ciliary body

what makes the scleral spur

sclera

what are the functions of the scleral spur

• act as an attachment for ciliary muscle and trabecular meshwork

• aids in aqueous humor drainage

what are the radial muscle fibers

interdigitating V-shaped bundles located posterior to the longitudinal muscle

what is the origin of the radial fibers

scleral spur

what is the insertion of the radial fibers

connective tissue near the posterior ciliary processes

where are the circular fibers locaated

they are closest to the lens

what is the origin of the circular muscle

scleral spur

what is the insertion of the circular muscle

connective tissue mid-ciliary processes

what is the action of the circular muscle

sphincter action

what happens when the ciliary body muscle contacts

causes the muscle ring to move inward, reducing tension on the zonular fibers (suspensory ligaments) that connect the ciliary body to the lens

lens becomes rounder → Focus on near objects

what happens when the ciliary body muscle relaxes

Relaxation of the ciliary muscle causes the muscle ring to expand outward.

As a result, zonular fibers (suspensory ligaments) connecting the ciliary body to the lens become taut

Lens becomes flatter → Focus on distant objects

what is the ciliary stroma continuous with

the iris and choroidal stroma (uveal tract)

what is the ciliary body not continuous with

anterior border layer of the iris

what does the stroma of the ciliary body have that the iris stroma also has

• type 1 collagen

• fibroblasts

• APCs

• melanocytes

• capillaries

how does the ciliary body capillaries differ from the iris capillaries

the ciliary capillaries are fenestrated and contribute to the aqueous

what layer of the ciliary body epithelium is continuous with the pigmented epithelium of the retina and with the anterior epithelium of the iris

outer pigmented layer

what junctions does the outer pigmented layer contain

desmosomes and gap

where does the basal aspect of the outer pigmented layer face

stroma of the ciliary body

what attaches the outer pigmented layer of the epithelium to the stroma of the ciliary body

basement membrane

what layer of the ciliary body epithelium is continuous with the posterior epithelium of the iris and the neural layers of the retina

inner non-pigmented layer

what junctions does the inner non-pigmented layer contain

• desmosomes

• tight junctions (not found in the pigmented layer)

• gap junctions

what does the basal aspect of the inner non-pigmented epithelium face

aqueous humor

what is in between the basal aspect of the inner non-pigmented epithelium and the aqueous humor

basement membrane (continuous with the internal limiting membrane of the retina and iris)

what happens to the pigment of the epithelium as you move from posterior iris epithelium to inner non-pigmented ciliary epithelum

you lose pigment

what is the difference in junctions between the iris and ciliary body

iris has prominently tight junctions while the ciliary has more gap

what are the ciliary processes

they arise from the ciliary body

what do the ciliary processes consist of

central core of stroma covered by a double layer of epithelium with the associated basement membranes

do the ciliary processes contain any capillaries

yes they contain large masses of small blood vessels that are fenestrated

what is the purpose of the ciliary processes

increase surface area

do the ciliary processes contain complete tight junctions and endothelial cell overlap

no

what contributes to the blood aqueous barrier

• the non-fenestrated iris capillaries

• tight junctions that connect the ciliary body non-pigmented epithelium

how does the aqueous humor move through the ciliary body

• there is high oncotic pressure inside the ciliary body stroma

• serum-derived proteins move around in the stroma

• the tight junctions of the inner epithelium and also the limiting membrane provide a barrier and keep the unneeded stuff from entering the aqueous

what are the functions of the ciliary body

• aqueous productions

• produces some vitreal components

• controls accommodation (ciliary body muscle)

what are the zonules

suspensory ligaments of the lens

what do they connect to

connect from limiting membrane of ciliary body to lens capsule

what is microphakia

small lens

what are zonules made of

• dense microfilaments

• fibrillin (has elasticity)

what is the origin and insertion of the orbiculoposterior zonules

• origin: ora serrata (limiting membrane)

• insertion: posterior capsule (ligament of Weiger)

what is the origin and insertion of the orbiculoanterior zonules

• origin: ciliary body pars plana

• insertion: anterior lens capsule

what is the origin and insertion of the cilioposterior zonules

• origin: ciliary body valleys (pars plicata)

• insertion: posterior lens capsule

what is the origin and insertion of the clioequatorial zonules

• origin: ciliary body valleys (pars plicata)

• insertion: equator

what are the auxiliary fibers

doesn’t involve the lens and gives stability for primary zonules

where are the orbiculociliary auxiliary zonule fibers located

from pars plana to posterior ciliary process

where are the interciliary auxiliary zonules fibers located

from ciliary process to process

what happens if our zonules tear

lens destabilization/luxation

what are the 2 types of destabilizations/luxations

anterior and posterior

what innervates the ciliary muscles

• contraction of ciliary muscle: parasympathetic

• sympathetic inhibits contraction