Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few invertebrates such as sponges, jellyfish, adult sea squirts and starfish do not have one, even if diffuse neural tissue is present. It is located in the head, usually close to the primary sensory organs for such senses as vision, hearing, balance, taste, and smell. The brain of a vertebrate is the most complex organ of its body. In a typical human the cerebral cortex (the largest part) is estimated to contain 15–33 billion neurons, each connected by synapses to several thousand other neurons. These neurons communicate with one another by means of long protoplasmic fibers called axons, which carry trains of signal pulses called action potentials to distant parts of the brain or body targeting specific recipient cells.
Read more about Brain.
Famous quotes containing the word brain:
“Progress celebrates Pyrrhic victories over nature. Progress makes purses out of human skin. When people were traveling in mail coaches, the world got ahead better than it does now that salesmen fly through the air. What good is speed if the brain has oozed out on the way? How will the heirs of this age be taught the most basic motions that are necessary to activate the most complicated machines? Nature can rely on progress; it will avenge it for the outrage it has perpetrated on it.”
—Karl Kraus (1874–1936)
“The true charm of pedestrianism does not lie in the walking, or in the scenery, but in the talking. The walking is good to time the movement of the tongue by, and to keep the blood and the brain stirred up and active; the scenery and the woodsy smells are good to bear in upon a man an unconscious and unobtrusive charm and solace to eye and soul and sense; but the supreme pleasure comes from the talk.”
—Mark Twain [Samuel Langhorne Clemens] (1835–1910)
“Always in England if you had the type of brain that was capable of understanding T.S. Eliot’s poetry or Kant’s logic, you could be sure of finding large numbers of people who would hate you violently.”
—D.J. Taylor (b. 1960)