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OA Quiz 2

Quiz 2

what does the anterior uvea and the posterior uvea consist of? anterior- iris and ciliary body; posterior- choroid
what 3 locations is the sclera attached to? anterior- sclera spur; posterior- at the optic nerve; exit of the vortex veins
what is the suprachoridal space? space b/w the sclera and the choroid
what is the supraciliary space? space b/w the ciliary body and sclera
what is the inner surface of the uvea lined with? anterior and posterior pigmented epithelium of the iris; nonpigmented and pigmented epithelium of the ciliary body, neurosensory retina, and retinal pigmented epithelium
what is the choroid composed of? blood vessels, melanocytes, connective tissue, and a mucinous extracellular fluid
what are the functions of the choroid? to nourish the outer layers of the retina; serves to exchange heat from the retina
what are there melanocytes in the choroid? they absorb excess light that penetrates the reina; prevents reflection
what are the 3 layers of the choroid? brunch's membrane, choriocapillaris and the vessel layer
what are the 5 layers of brunch's membrane? basement membrane of the endothelium of the capillaries of the choriocapillaris, an outer collagenous layer, a meshwork of elastic fibers, an inner layer of collagen fibers, basement membrane of the RPE
where is drusen deposited? b/w RPE and inner layer of collagen
what is the function of the brunch's membrane plays a part in the passage of fluid from the choriocappilaris to the retina
are there nerve fibers in brunch's membrane? no
what is the choriocapillaris layer? a single layer composed of capillaries with sac-like dilation
where are the capillaries from the capillary layer from? they are fed by arteries from the vessel layer
are the capillaries from the capillary layer fenestrated? yes
are the vessels in the iris vasculature fenestrated? no
describe the capillaries in the ciliary body anterior- capillaries are fenestrated for the production of aqueous humor ; posterior- capillaries are non-fenestrated
what is the function of the choriocapillaris? sole provider of nutrients to the macula
the choriocapillaris is a lobulated network. what happens if one lobule is destroyed? the others remai intact b/c they are not anastomosed
what is the vessel layer? a layer of loose connective tissue containing numerous melanocytes in which blood vessels are situated
what are the 2 layers of the vessel layer? an inner layer of medium-sized vessels (satteler's layer) and an outer layer of large vessels (Haller's layer)
arteries that feed the vessel layer are branched from what? short posterior ciliary arteries
what are muscle stars? they are branched stellate figures located in the anterior suprachoroid lamina; they represent the posterior termination of the longitudinal muscle of the ciliary body
veins in the choroid carry blood via what? vortex veins
what is the choroid innervated by? long and short posterior ciliary nerves
is the choroid autoregulated or neuroregulated? neuroregulated!
what does the ciliary body do? formation and secretion of the aqueous humor
functions of the ciliary body? provides musculature needed for accommodation; attachment site for lens zonules; synthesizes lens zonules and hyaluronic acid
boundaries of the ciliary body? extends from the root of the iris and posteriorly to the choroid
ciliary body is longer in the temporal half or the nasal side ? temporal side
what is the supraciliary lamina? loose attachments of the outer surface of the ciliary body to the lamina fusca of the sclera
what are the 2 regions of the ciliary body? anterior- pars plicata; posterior- pars plana
what are ciliary processes? fin-like ridges that project into the posterior chamber of the eye on the pars plicata
what is secreted at the crest of the ridges of the pars plicata? aqueous humor
what are minor processes? smaller processes that are present b/w the ciliary processes
where do zonular fibers from the ocular lens travel? b/w ciliary processes
where does the posterior edge of the pars plana look scalloped at the ora serrata? on the nasal side!
what scallops of the nasal pars plana consist of? central bay and dentate processes
what is the ciliary sulcus? used for increase stabilization when the intraocular lens cannot be placed in the capsular bag
where is the ciliary sulcus located? located posterior to the iris; bound posteriorly by the ciliary processes and anterior zonular fibers and lens surface
what layers do the ciliary body consist of? a bilayered eptihelium (NPE and PE), stroma, and musculature
what are the characteristics of the NPE? junctional complex with the PE, apices of PE and NPE face each other, base of NPE is covered by the internal limiting membrane of the ciliary body, is a continuous layer that stretches from the root of the iris to the ora serrata, decrease melanin granule
what are the characteristics of the PE? cells are cuboidal, continuous with the RPE, zonula occludens not found, not part of the blood-aqueous barrier, covered by basement membrane
what is the ciliary body stroma continuous with? anteriorly- iris stroma; posterior- choroid at the ora serrata
what does the major circle of the iris supply to the anterior and posterior arteriole of each ciliary process? anterior arteriole- supplies the tip of the ciliary process with fenestrated capillaries; posterior arteriole- supplies ciliary muscle with non-fenestrated capillaries
what branches form the major arterial circle of the iris? anterior ciliary and long posterior ciliary arteries
what does the ciliary body musculature compose of? longitudinal, radial and annular muscle fibers
what are the characteristics of longitudinal muscle fibrs? called Bruche's fibers, lie adjacent to the supraciliaris, have a "V" shape, apex of fiber originates in epichoroidal stars, base will insert at the scleral spur and trabecular meshwork
what are the characteristics of radial muscle fibers? have shorter "V", originates from sclera spur and inserts into connective tissue
what are the characteristics of annular muscle fibers? lie close to the peripheral edge of the crystalline lens, have a sphincter like action during accom.
what does the iris do? separates the anterior and posterior chamber of the eye; provides eye color
what are the characteristics of the papillary aperature? displaced inferonasally, regulated by movement of iris
where is the iris the thickest at? iris collarette
what is the iris collarette? a circular ridge that divides the iris into a papillary zone and a ciliary zone
where is the iris the thinnest? near its insertion into the ciliary body, known as the root of the iris
how does a blue color iris appear blue? it absorbs longer wavelength
what are enclosing depressions in the anterior iris surface known as? Fuch's crypts
why is the papillary displaced slightly anterior to the frontal plane of the iris root? it rests on the lens
describe the posterior iris surface much smoother and more uniform than the anterior surface of the iris
what are the 5 layers of the iris? 1. anterior border layer 2. iris stroma 3. muscle layer 4. dilator muscle and anterior pigment ep. 5. posterior pigment ep.
characteristics of the anterior border layer of the iris? is a condensation of the underlying stroma, composed of fibroblasts, melanocytes and collagen fibrils, terminates at the iris root, absent at the fuch's crypts
characteristics of the iris stroma? composed of connective tissue that contains pigmented and non-pigmented cells, continuous peripherally with the stroma of the ciliary body, arteries supplied from the major circle of the iris
characteristics of the muscle layer of the iris? composed of spindle-shaped smooth muscle, joined by gap junctions, innervated by postganglionic parasympathetic fibers carried in short posterior ciliary nerves
what is contraction of the iris muscle known as? miosis
characteristics of the dilator muscle and anterior pigment ep. mascular basal portion- makes up the iris dilator muscle; anterior pigment ep- apical portion apposes the apical surface of the posterior pigment ep., joined together by tight junctions and desmosomes
what is the dilator innervated by? by the long posterior ciliary nerves of CN V. these nerves carry postganglionic sym. innervations from the superior cervical ganglion
what are the characteristics of the posterior pig ep? more heavily pigmented than the anterior, cells are columnar, contains large pigment granules, joined by desmosomes and tight junctions, transitions to the NPE of the ciliary body
what supplies blood to the iris? 2 long posterior ciliary arteries and 7 anterior ciliary arteries that merge from the major circle of the iris
how are arterial vessels kept from kinking? from the collagen fibrils that surrouind and anchor the vessels in place
are arterioles in the iris non-festestrated or fenestrated? non-fenestrated! part of the blood-aqueous barrier
what are endothelial cells of the iris joined by? tight junctions
what innervates the dilator muscle of the iris long posterior ciliary nerves of CN V
what innervates the sphincter muscle of the iris? short ciliary nerves from the ciliary ganglion
what does the AH provide nutrients for? avascular lens, cornea, trabecular meshwork
how does the AH travel in the anterior chamber? by convective flow current;rises posteriorly due to the warm iris vasculature and falls anteriorly behind the cooler corneal endothelium
what is the rate of secretion of the AH? 2.5 to 30 microliters/min; entire aqueous compartment is overturned ever 100 mins
vol of posterior chamber? 50 microliters
vol of anterior chamber? 200-250 microliters
what does the iridocorneal angle consist of from top to bottom? schwalbe's line, trabecular meshwork, sclera spur, ciliary body band, iris root
volume of VH 4ml
what are the 3 vitreous zones? what do they differ by? cortex (hyaloids surface), intermediate zone, and cloquet's canal ; differ in relative density
describe the anterior and posterior cortex of the cortex zone of VH anterior- adjacent to the ciliary body, posterior chamber and lens; posterior- in contact with the retina
what is the hyaloideocapsular ligament an annular attachment b/w the posterior lens capsule and anterior face of the vitreous
what is the space of berger potential space within the center of the hyaloideacapsulare ligament ; formed b/c the vitreous and lens are juxtaposed rather than joined
what is the patellar fossa the depression that the lens makes within the anterior vitreous
what is the vitreoretinal interface outermost portion of the posterior cortex that contains anchoring fibrils that merge with the internal limiting membrane of the retina
where are the vitreal attachments? at the vitreous base, around the optic disc, blood vessels, and the macula
what is the weiss ring the white ring that is present by posterior vitreal detachment around the optic disc
what does the cloquet's canal formly contain? hyaloids vasculature that fed the lens during embryological dev
what contributes to the viscoelastic properties of the vitreous? the combination of hyaluronic acid and collagen
what happens to the vitreous as you age? it becomes more watery
what are the dimensions of the lens? 10mm in diameter; 4mm thick
does the lens change with age? diameter does not change; thickness increases 0.02mm per year
what is used to keep the pens in position suspensory ligaments of the lens (the lens zonules)
what causes the lens to change shape? malleability of the lens and the contraction of ciliary muscle
what is the lens power? 15 to 20D of the total power
what are the 3 parts of the lens? elastic capsule, lens epithelium, and lens fiber
what are the characteristics of the elastic capsule? no elastic fibers, thickest basement membrane in the body, there is no posterior epithelium, lens is secreted by the anterior lens epithelum (anteriorly) and superifical lens fiber (posteriorly), anterior lens capsule increases in thickness, with age
what are the characteristics of lens fibers? secondary fibers that constitute the bulk of the lens, originate from the epithelium at the equator, nucleus of the lens fiber gradually disintegrates, older fibers are towards the center, opposing lens fibers produce sutures
describe the anterior suture and the posterior suture in the fetus nucleus anterior suture- upright Y; posterior suture- inverted Y
what is the function of the lens epithelium? epithelium divides and differentiates into secondary lens fibers, central anterior ep tranport substances from AH to lens interior, secretes lens capsule
what is the epithelium-fiber interface? the border b/w the apical portion of the anterior ep and the apical portion of the secondary lens fiber
what are the characteristics of the epithelium fiber interface? nutrients and ions are exchanged across this surface, gap-like junctions are present on the apical portion of the ep and fibers
what contributes to the differences in the refractive index of lens? the non uniform distribution of crystallins
what happens as lens fibers develop? their nuclei are lost and organelles of the fiber become specialized to form crystallins
what are the divisions of the lens? embryonic nucleus, fetal nucleus, adult nucleus and lens cortex
which 2 divisions of lens does not increase in size? embryonic nucleus and fetal nucleus
what is the lens cortex? fibers that are newly formed containing nuclei that surround the adult nucleus
blood supply to the crystalline lens? no blood supply; dependent on the AH
Created by: babytigger131



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