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Article: Central Nervous System
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- Biology
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CopyrightCOPYRIGHT 2002 The Gale Group Inc. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
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Central Nervous System
The central nervous system (CNS) consists of a brain and spinal (nerve) cord. Most invertebrates and all vertebrates have sensory and
motor neurons
that are linked by way of a CNS. Most invertebrates have a CNS that is organized into a brain and a longitudinal nerve cord that is
ventral to
the digestive system, whereas chordates have a spinal cord that is hollow and
dorsal to
the digestive system. The CNS processes input from the internal and external environments, integrates information, and controls the body's responses through
efferent
pathways to the body.
The brain is protected by the skull in vertebrates. The head is usually first to make contact ...