Flashcards in Exam 1 Remington- Uvea Deck (103):
What is the extent of the iris?
Iris root (junction of iris with choroid) and pupillary ruff (circle around the pupil)
The ruff is ______ to the root
What are the two anatomical portions of the iris separated by the collarette?
Pupillary and ciliary
What is the collarette?
Attachment site for embryologic membrane
Pupillary portion of the iris
Portion surrounding the pupil
Ciliary portion of the iris
From collarette to the root
What is the composition of the anterior border layer of the iris?
CT, Fibroblasts and melanocytes
Iris processes extend into ____ ____ in the periphery
What is the composition of the iris stroma?
Loose CT, collagen fibers arranged in trabeculae, melanocytes, clump cells, non-pigmented fibroblasts
What are clump cells likely?
What are structures located in the iris stroma?
Blood vessels and sphincter muscle
Stomal ____ bundles encircle walls of arterioles and venules
What is the origin of iris arteries?
Major circle of the iris
What is the minor circle of the iris?
Incomplete circular vessel within iris stroma
The minor circle of the iris is a remnant of _______ development
What is the composition of the sphincter muscle?
Circular muscle, encircles the pupil
What is the action of the sphincter muscle?
Contracts to get miosis
What is the myoepithelium?
Anterior iris epithelium
What is the basal portion of the anterior iris epithelium?
Where is the dilator muscle located?
From root to midpoint below sphincter
What is the action of the dilator muscle?
Mydriasis, radially oriented
What is the origin of the dilator muscle?
What type of cells are in the posterior iris epithelium?
Cells of the posterior iris epithelium are joined by what?
How are the 2 layers of the epithelium positioned?
How are the 2 layers of the epithelium joined?
To each other via desmosomes
Innervation of the iris sphincter
Innervation of the iris dilator
What are crypts in the anterior iris surface?
Openings in the anterior border layer
Crypts of Fuch
On both sides of collarette
In anterior border layer
Anterior iris surface has _____ contraction folds
Posterior iris surface has ____ contraction furrows in ____ zone
Posterior iris surface has ___ furrows in the _____ zone
Posterior iris surface has _____ contraction folds
How is iris color determined?
Density of melanin in melanocytes
What types of collagen trabeculae are there?
Blue, brown, green and gray
Blue iris color
Occurs because of back scatter of incident light (Rayleigh scatter)
Brown iris color
Due to absorption of light by melanocytes
Green and gray iris color
Various amount of absorption and scatter
What happens in iris transillumination?
Loss of epithelial pigment is evident
Trembling of the iris
What are anterior iris synechiae?
Usually peripheral, block aqueous from getting into aqueous of anterior chamber and exiting
What are posterior iris synechiae?
Adhesion between posterior iris and the lens
Difference in color between the eyes
Heterochromia could be a sign of what?
What is the extent of the ciliary body?
From iris root to ora serrata
What is the shape of the ciliary body?
Triangular in cross section
What is the base of the ciliary body?
Corner at scleral spur, spans across processes
What is the apex of the ciliary body?
At the ora serrata, where the ciliary body ends and choroid begins
Where is the outer side of the ciliary body?
Runs along sclera
What is the inner side of the ciliary body?
Runs along posterior chamber
What is in the pars plana of the ciliary body?
Contains 70-80 processes, Valleys of Kuhnt- continuous with furrows and folds
What is in the pars plana of the ciliary body?
Dentate processes, oral bays
What is the location of the supraciliaris?
Outermost layer, adjacent to the sclera
What is the composition of the supraciliaris?
CT, ribbon-like bands of collagen, oblique bands
What is the function of the supraciliaris?
Allows muscle to slide against sclera
What is the composition of the ciliary muscle?
Three muscle layers are described but are not truly separate
What is the origin and insertion of the longitudinal muscle fibers (of Brucke) outer ciliary muscle?
Origin: scleral spur, Insertion: anterior choroid in stellate processes
What is the origin and insertion of the radial fibers in the ciliary body?
Origin: scleral spur, Insertion: Ciliary body stroma
What is the location of the Mueller's annular muscle (inner) of the ciliary body?
In ciliary body stroma near major circle of the iris
What is the function of the ciliary muscle?
Change the shape of the lens, accommodation
What is parasympathetic innervation of the ciliary muscle?
Causes the muscle to contract
What is the sympathetic innervation of the ciliary muscle?
Decreases muscle tone
Where does the ciliary stroma extend into?
What is the composition of the ciliary stroma?
Vascular CT, lymphatic channels
What is the vascular CT like in the ciliary stroma?
Capillaries in processes are fenestrated and wide-lumened
Lymphatic channels have been discovered in the ciliary stroma and are possible route for ______ exit
The ciliary epithelium layers are _____
What is the outer ciliary epithelium?
Pigmented, continuous with the anterior iris epithelium and the RPE
What is the inner ciliary epithelium?
Non-pigmented, continuous with posterior iris epithelium and neural retina
What is the role of the pigmented ciliary epithelium?
Intercellular junctions (desmosomes and gap junctions), role in aqueous production
What is the role of the non-pigmented ciliary epithelium?
Intercellular junctions (desmosomes, gap junctions, joined by zonular occludens), prodcues and secretes aqueous humor
What are the 2 functions of the ciliary body?
Aqueous production and accommodation
What is the blood aqueous barrier in the ciliary body?
Selectively controlled substance secreted as aqueous, fenestrated ciliary body capillaries permit large molecules to exit blood, ZO joining cells of the non-pigmented epithelium (this is one way to control amount of protein in aqueous conc is slight compared to blood), non-fenestrated iris capillaries prevent large molecules from entering aqueous
The lens is attached to the ciliary body via ______
What happens when the ciliary muscle contracts?
Reduction in diameter of ciliary body, tension in zonules is released, lens thickens and increases in power
What is the location of the choroid?
Inner to sclera and outer to retina
What is the extent of the choroid?
From ora serrata in ciliary body to optic nerve
What is another name for the suprachoroid lamina?
What is the suprachoroid lamina continuous with?
Sclera and choroidal vessels
What is the composition of the suprachoroid lamina?
Diagonally oriented bands
The suprachoroidal space (perichoroidal space) is a ______ space
What is the choroidal stroma continuous with?
Suprachoroid and choriocapillaris
What does the choroidal stroma contain?
Haller's layer (large-lumened vessels), Sattler's layer (medium-lumened vessels), and vortex veins
Where is the choriocapillaris located?
Only in the choroid
What are 3 characteristics of the choriocapillaris?
Anastomosing, wide-lumened, and fenestrated (diaphragm-covered windows)
What are the 5 layers of Bruch's membrane?
BM of choriocapillaris, outer collagenous zone, elastic layer, inner collagenous zone, and BM of RPE
What are the functions of the choroid?
Provides nutrients to and eliminates waste from outer retina, absorbs excess light
What are two causes of degeneration in Bruch's membrane?
What causes drusen?
Accumulation of waste matter which displaces the retina
What is the appearance of drusen?
Yellow- white dots, spots in the retina
What causes AMD?
Degeneration in Bruch's in macular area, normally nutrients pass through Bruch's from choriocapillaris into retina, waste products go in the other direction, with age phospholipids accumulate in Bruch's causing it to become hydrophobic (defective phosphorylation process)
What are 2 possible consequences of AMD?
Fluid accumulates between Bruch's and RPE that may lead to retinal detachment, neovascularization from choriocapillaris (leaky vessels -> hemorrhage into retina)
What are risk factors for AMD?
Genetics, age, UV exposure, Light pigmentation
What is the treatment of AMD?
Antioxidant supplements may slow the progression (lutein and zeaxanthin)
What were the conclusions of AREDS?
Determined that high doses of lutein and zeaxanthin reduced the risk of AMD progression
What were the conclusions of AREDS2?
Suggested that lutein, zeaxanthin plus omega-3-fatty acids (fish oil) can slow or prevent AMD, formulations containing beta carotene increased incidence of lung cancer in smokers, formulations containing omega-3-fatty acids had no affect on AMD reduction and might increase risk of bleeding
What are 4 facts from the news release from NIH?
Laser treatment for neovascularization, photodynamic therapy, vascular endothelial growth factor antagonist, submacular surgery to remove BV network
What happens in laser treatment for neovascularization?
Laser burns "spot weld" leaky spots, indocyanine green dye injected to better visualize BVs
What happens in photodynamic therapy?
Visuodyne is injected and adheres to abnormal vessel wall, laser activates substance and closes BV