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52 Cards in this Set
- Front
- Back
What happens embryologically on day 25?
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the edges of the neural fold comes together, the neural ectoderm comes into close contact with surface ectoderm
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The retina and optic nerve develops as an outpocket of what?
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the diencephalon
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What does the optic vesicle cuase?
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the differentialtion of the overlying surface ectoderm to form the lens placode
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What does the lens placode give rise to?
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the lens vesicle
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What will the lens vesicle form?
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the primitive lens
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What happens to the optic vesicle?
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it invaginates and forms the 2-layer optic cup
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What are the two layers of the cornea derived from?
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outer-surface ectoderm
inner-neural crest cells |
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what do the iris and the ciliary process form from?
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the outer rim of the optic cup
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What are the components of the external layer?
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sclera, cornea (avascular, densely innervated by V)
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What are the components of the middle layer?
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choroid capillaries, ciliary body, stroma of iris
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What are the components of the inner layer?
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retinal pigment epithelium and the neural retina
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What produces aqueous humor?
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ciliary body
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What are the boundaries of the anterior chamber?
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the cornea and the iris
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What are the boundaries of the posterior chamber?
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iris and lens
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What are the boundaries of the vitreous body?
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lens to retina
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What mediates accomadation?
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the capsule surrounding the lens
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Which cells are responsible for the production of the new lens cortical fibers?
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E-cells
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What is the state of the ciliary muscle need to see in the distance?
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relaxed, lens is thin and the curvature is reduced
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What is the state of the ciliary muscle needed to see near?
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contracted, lens is relaxed with greater curvature
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What is myopia?
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optical power of the lens is abnlly strong
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How do you correct myopia?
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concave, diverging lens
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What is hyperopia?
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optical power is abnlly weak
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How do you correct hyperopia?
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converging, convex lens
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What is a stigmatism?
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optical power of the lens is heterogenous
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How do you correct astigmatism?
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cylindrical lens
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What is amblyopia?
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visual deficit in one eye
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What does amblyopia cause?
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cataract, ptosis, strabismus, refractor errors
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The cornea uses what type of metabolism?
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aerobic
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The lens uses what kind of metabolism?
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anerobic
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What is the function of the retinal epithelium?
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metabolically supports photoreceptors and forms blood-retinal barrier
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What are the two classes of the ganglion cell?
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Large Y and Small X
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What is the function of the large Y ganglion cell?
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movement of light
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What is the function of the small X ganglion cell?
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color discrimination
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Where do the Large Y cells project to ?
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Magnocellular of LGN
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Where do the Small X cells project to?
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Parvocellular of LGN
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When are rods responsive?
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moonlight levels of intensity
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What is the pigment associated with rods?
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Rodopsin
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What does a photon do to Rodopsin?
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it isomerizes it to metarodopsin II
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What happnes to 11-cis-rentinal?
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it is converted to all-trans retinal
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What does metarodopsin II do?
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it activates tranducin
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What does transducin do?
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it decreases cGMP levels
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What happens when cGMP levels dec?
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it closes cGMP-gated ion channels, hyperpolarizing the PR
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What happens when the PR is hyperpolarized?
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it releases less glutamate
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What myelinates optic nerver?
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oligodendrocytes
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What would happen if the optic nerve was lesioned?
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one whole eye would be blind
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What does a pituitary tumor cause?
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bitemporal heteronymous hemianopsia
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Where do 10% of the fibers from the retina go?
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superior colliculus
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Which layers of the LGN do the parvocellular ganglion cells project to?
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outer 4 laminae
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Where do the magnocellular ganglion cells project to?
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inner 2 layers
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Which lamina receive from ipilateral eye?
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2,3,5
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Which lamina receive from contralateral eye?
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1,4,6
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What should you think when there is macular sparing?
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cortical lesion
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