Ciliary Body Flashcards
what is the main function of the ciliary body
to form and secrete aqueous humor and enhance the outflow
what functions of the ciliary body have been suggested
it may be involved in synthesizing lens zonules and hyaluronic acid of the vitreous humor
where in the uvea is the ciliary body
intermediate portion
which side of the eye (temporal or nasal) is the ciliary body longer
temporally by 1mm
what is the supraciliary lamina
where there are loose attachments from the outer surface of the ciliary body and the lamina fusca (sclera)
where is the supraciliary space
between the supraciliary lamina and the lamina fusca
what is the pas plicata
begins at the iris root and has fin-like projections/ridges that go into the posterior chamber
what is a ciliary process
the fin-like projection from the pars plicata
where is the aqueous humor secreted
from the ciliary processes
how many ciliary processes are there per eye
about 70-80
what travels between the ciliary processes
the lens zonules from the lens
what is the pars plana
the posterior continuation of the ciliary body from the pars plicata
what is at the nasal edge of the pars plana
the scallopes of the ora serrata (the temporal side is straight)
what is the central bay/ora bay
the scallopes of the ora serrata
what are dentate processes
retinal teeth in between the ora bays
where is the ciliary sulcus
posterior to the root of the iris
what is the ciliary sulcus used for
placement of haptics from IOL’s when they cannot be placed in the capsular bag
does the ciliary body have a bilayered epithelium
yes- nonpigmented and pigmented ciliary epithelium
which direction does the base of the nonpigmented epithelium face
the posterior chamber
what connects the PE and NPE
junctional complexes that keep the potential space between them from separating and gap junctions
why do the apices of the PE and NPE face each other
they were derived from a single layer during embryological development
what does the base of the PE face
the ciliary stroma
the NPE is a continuous layer with which layers
the posterior pigmented iris epithelium turns into the NPE and that turns into the retina
how are the NPE cells joined
tight junctions at the apex and desmosomes at the base
why do the NPE cells have tight junctions
to form the blood-aqueous barrier for the ciliary body
what is the primary component of the blood aqueous barrier
the zonula occudens (tight junctions)
why do the NPE and PE have gap junctions
to work in metabolic concert and work in tandem to create the aqueous humor
what shape or the PE cells
cuboidal
what is the PE layer continuous with
the anterior pigmented iris epithelium turns into the PE and then it is the RPE
do the PE cells have tight junctions
no, they are not part of the blood aqueous barrier
how is the ciliary stroma classified
it is loose areolar connective tissue and continuous with the iris stroma
why does the ciliary stroma continue into each ciliary process in the pars plicata
to carry the vascular supply that gives rise to the fenestrated capillaries that leak source material to make/secrete aqueous humor
what does the major arterial circle (MAC) supply to each ciliary process
an anterior and posterior arteriole
is the anterior arteriole fenestrated
yes, it is larger than the posterior and supplies the tip of the process (fenestrated for the formation of aqueous humor)
is the posterior arteriole fenestrated
no, it is the vascular supply to the ciliary muscle
what forms the major arterial circle of the iris
branches of the anterior ciliary and long posterior ciliary arteries
what is the bulk of the ciliary body
the ciliary muscle
what type of muscle is found in the ciliary body
smooth muscle (3 types)
what is the outer most muscle of the ciliary muscles
the longitudinal or Brucke’s fibers
where is the apex of the longitudinal muscle located/where does it originate
from stellate structures called epichoroidal stars that are located in the anterior 1/3 of the choroid
where does the longitudinal muscle insert (the base)
in the scleral spur and the trabecular meshwork
what happens to the longitudinal muscles during accommodation
contraction pulls on the trabecular meshwork and increases the size of the openings so the aqueous humor can exit the eye more readily (decreasing IOP)
where do the radial muscle fibers originate
in the scleral spur
where do the radial muscles insert
into connective tissue near the base of the ciliary processes of the pars plicata
what are the inner most muscle fibers
the annular or circular muscle fibers
where is the circular muscle located
close to the peripheral edge of the lens
what is the action of the annular or circular muscles
sphincter like action during accommodation, mostly involved in accommodation
