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:
“What do the botanists know? Our lives should go between the lichen and the bark. The eye may see for the hand, but not for the mind. We are still being born, and have as yet but a dim vision of sea and land, sun, moon, and stars, and shall not see clearly till after nine days at least.”
—Henry David Thoreau (1817–1862)
“Your real statesman is first of all, and chief of all, a great human being, with an eye for all the great fields on which men like himself struggle, with unflagging, pathetic hope, toward better things.... He is a guide, a counselor, a mentor, a servant, a friend of mankind.”
—Woodrow Wilson (1856–1924)
“Love not me for comely grace,
For my pleasing eye or face,
Nor for any outward part:
No, nor for a constant heart!”
—Unknown. Love Not Me for Comely Grace (l. 1–4)