Lecture 8: 12/8 Flashcards
the corrugated (rough surface) pattern of the basement membrane of the ciliary body pigmented epithelium is called
reticulum of Mueller
what type of cells are found in the pigmented epithelium layer and how many layers of the cells are there?
it is a dark layer of cuboidal epithelium cells, single layer
the pigmented cuboidal epithelium cells continue forward to become the
iris, anterior epithelium
the pigmented cuboidal epithelium cells continue posterior to become the
RPE
what is found in the apex of the pigmented cuboidal epithelium layer cells?
dark pigmented granules with melanin pigment (the apex pointing internally)
explain how the white stripe appears on the pigmented epithelium layer?
at the top (the summit) of the ciliary processes there is less pigment
what do you find at the lateral walls between pigmented epithelial cells?
a few interdigitations and some desmosomes
which epithelium layer of the ciliary body has more organelles such as mitochondria and endoplasmic reticulum?
the nonpigmented epithelium
is the pigmented or nonpigmented epithelium the most internal of the epithelial layers of the ciliary body?
the nonpigmented epithelium
the nonpigmented epithelium continues anteriorly into the iris as
the posterior pigmented epithelium
the nonpigmented epithelium continues posteriorly as the
nervous part of the retina
the tight seals between the NPE with the desmosomes and interdigitations forms the:
blood-aqueous barrier
in the NPE:
-the cells are _____ in the pars plicata and ______ in the pars plana
- cuboidal in pars plicana
- columnar in pars plana
what are the 3 components of the aqueous humor?
- filtration
- ultrafiltration
- secretion
where does filtration of aqueous humor occur?
it is coarse and occurs in capillaries in the ciliary processes
where does ultrafiltration of aqueous humor occur?
finer process of fluid going in to epithelial cells
describe secretion of aqueous humor
an active process using cell energy to pump fluid out of NPE into chamber
what nervous control system causes the ciliary body to contract?
autonomic parasympathetic
the iris is a continuation anteriorly of the
vascular tunic
list 3 functions of the iris
- diaphragm
- amount of light- wide range illuminance
- aberrations
miosis is
to decrease the aperture, make the pupil smaller, increases depth of field/focus
triad for focusing at near
- convergence
- accommodation
- miosis
mydriasis
decreased illuminance causes increased size of pupil
the pharmaceutical drug used to dilate is called a
mydriatic drug
embryology of pupil formation
there is a sheet of mesoderm that covers the eye and it atrophies away to form the pupil, atrophy varies from person to person
crypts are
deep excavations that result from localized atrophy of the mesodermal layer
which layer of the iris has the darker pigmentation?
the posterior layer
the iris continues forward from the middle of the anterior face of the pars plicata. this is called the
root of the iris
the root of the iris is the thinnest part and is ____mm thick
0.5mm
average diameter of the iris is about
12mm
the aqueous humor, which is constantly produced by the ciliary body in the _____ chamber must make its way through the pupil into the _____ chamber to a drainage system
posterior ->
anterior
the pupil is eccentrically placed, meaning
the pupil is displaced towards the nasal side
describe a good demonstration of how the margin of the iris is resting on the lens
after cataract surgery- someone with iridonesis has the iris waving around because it may not have the support of the lens anymore
how can dilation cause aqueous flow problems?
it can stiffen the iris and out more pressure against the lens which can cause a flow of the fluid in the aqueous chamber
the thinnest part of the iris (where trauma can rip it) is called the
root of the iris
iridodyalis is
a tear of the root of the iris
the peripheral edge of the iris is attached to the:
ciliary body
is the central edge of the iris (pupillary margin) attached to anything?
no it is free and surrounds the aperture called the pupil
