Sleep
Sleep is a naturally recurring state characterized by reduced or absent consciousness, relatively suspended sensory activity, and inactivity of nearly all voluntary muscles. It is distinguished from quiet wakefulness by a decreased ability to react to stimuli, and is more easily reversible than being in hibernation or a coma. Sleep is a heightened anabolic state, accentuating the growth and rejuvenation of the immune, nervous, skeletal and muscular systems. It is observed in all mammals, all birds, and many reptiles, amphibians, and fish.
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Famous quotes containing the word sleep:
“There dwell the children of the dark Night, the dread gods Sleep and Death.”
—Hesiod (c. 8th century B.C.)
“The City is of Night, but not of Sleep;
There sweet sleep is not for the weary brain;
The pitiless hours like years and ages creep,”
—James Thomson (1834–1882)
““What care I for a goose-feather bed,
With the sheet turned down so bravely, O?
For to-night I shall sleep in a cold open field,
Along with the wraggle taggle gipsies, O!””
—Unknown. The Wraggle Taggle Gipsies (l. 33–36)