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The Eye - Coggle Diagram
The Eye
Diseases/ conditions
Hyperopia- farsightedness, short eyeball
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Myopia- near sightedness, long eyeball
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Glaucoma- irreversible damage to optic nerve, build up of aqueous fluid, block canal of Schlemm
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Structures
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Iris-The colored part of the eye which helps regulate the amount of light entering the eye. When there is bright light, the iris closes the pupil to let in less light. And when there is low light, the iris opens up the pupil to let in more light.
Cornea-The clear front window of the eye which transmits and focuses (i.e., sharpness or clarity) light into the eye.
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Ciliary Body-Structure containing muscle and is located behind the iris, which focuses the lens.
Macula-The area in the retina that contains special light-sensitive cells. In the macula these light-sensitive cells allow us to see fine details clearly in the center of our visual field.
Choroid-Layer containing blood vessels that lines the back of the eye and is located between the retina and the sclera
Optic Nerve-A bundle of more than a million nerve fibers carrying visual messages from the retina to the brain,
Pupil-The dark center opening in the middle of the iris. The pupil changes size to adjust for the amount of light available
Sclera-The white outer coat of the eye, surrounding the iris.
Retina-The nerve layer lining the back of the eye. The retina senses light and creates electrical impulses that are sent through the optic nerve to the brain.
Vitreous Humor-The, clear, gelatinous substance filling the central cavity of the eye.
Photoreceptors of Retina
Cones- blue(short waves), Green(medium waves), red(long waves), responsible for color vision, concentrated in fovea central's, use photopsin
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Rods- black/white vision in dim light, use Rhodopsin= retinaldehyde (Vitamin A)+ opsin
neural pathway
Light waves→cornea→aqueous humor in anterior eye chamber→pupil (dilates in
dim light via sympathetic stimulation of radial muscles in iris); constricts in bright light via parasympathetic stimulation of circular muscles in iris)→lens (changes shape; accommodation – bends light rays so they focus on the retina)→vitreous humor of posterior chamber→photoreceptors on retina (rods and cones)→Action potentials travel along bipolar cells to ganglion cells to optic nerve at optic disc→1. superior colliculus, 2. Thalamus→visual cortex in occipital lobe