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6 Cards in this Set

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  • Back
Where do retinal vessels originate from?
A pale circular region called the optic disk.
What properties of the optic disk inhibit the sensation of the light from occuring? (At least 2 reasons)
1) No photoreceptors found on the optic disk
2) Large blood vessels exist because the vessels cast shadows on the retina
Why is the macula the part of the retina for central vision?
1) The macula is distinguished by the relative absence of large blood vessels thus improving the quality of central vision.
Describe how the cornea is able to refract light
Light coming into the eye is roughly parallel. Inside the cornea is aqueous humor which bends the light (which depends on the angle of curvature of cornea and [ ] of aqueous. Ultimately all light must converge at retina.
Describe accommodation by the lens
To focus the eye on a distant point, relatively little refraction is required, and it is provided by a FLAT lens (due to relaxation of ciliary muscles)
Near objects require greater refraction provided by a more SPHERICAL lens (due to the contraction and swelling of the ciliary muscles).
Name a simple optical procedure to check for signs of serious neurological disorder involving the brain stem.
Connections between the retina and neurons in the brain stem control the muscles that constrict the pupils. This constriction and dilation is consenual; which means if one one is stimulated for pupil dilation the other eye must also dilate even if it wasnt stimulated...if it doesn't, this may be a sign of serious neurological disorder involving the brain stem.