Eye
Eyes are organs that detect light and convert it into electro-chemical impulses in neurons. The simplest photoreceptor cells in conscious vision connect light to movement. In higher organisms the eye is a complex optical system which collects light from the surrounding environment, regulates its intensity through a diaphragm, focuses it through an adjustable assembly of lenses to form an image, converts this image into a set of electrical signals, and transmits these signals to the brain through complex neural pathways that connect the eye via the optic nerve to the visual cortex and other areas of the brain. Eyes with resolving power have come in ten fundamentally different forms, and 96% of animal species possess a complex optical system. Image-resolving eyes are present in molluscs, chordates and arthropods.
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Famous quotes containing the word eye:
“The gap between the committed and the indifferent is a Sahara whose faint trails, followed by the mind’s eye only, fade out in sand.”
—Nadine Gordimer (b. 1923)
“There are a thousand unnoticed openings ... which let a penetrating eye at once into a man’s soul; and I maintain ... that a man of sense does not lay down his hat in coming into a room,—or take it up in going out of it, but something escapes, which discovers him.”
—Laurence Sterne (1713–1768)
“The Demon arose from his wallow to laugh,
Brushing the dirt from his eye as he went;
And well I knew what the Demon meant.”
—Robert Frost (1874–1963)