Central nervous system

<p>The central nervous system (CNS) is the part of the <a href="/facts/Nervous_system/CDxRKU2U">nervous system</a> consisting primarily of the <a href="/facts/Brain/EKla9NkJ">brain</a>,  <a href="/facts/Spinal_cord/XbWLr917">spinal cord</a> and <a href="/facts/Retina/v0ISNX2S">retina</a>. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all parts of the bodies of <a href="/facts/Bilateria/nfUwVYrx">bilaterally symmetric and triploblastic animals</a>—that is, all multicellular animals except <a href="/facts/Sponge/E9T2WFWA">sponges</a> and <a href="/facts/Coelenterata/89tVkW0k">diploblasts</a>. It is a structure composed of <a href="/facts/Nervous_tissue/YY7qG0WD">nervous tissue</a> positioned along the <a href="/facts/Anatomical_terms_of_location/IpJ1fq2f">rostral (nose end) to caudal (tail end)</a> axis of the body and may have an enlarged section at the rostral end which is a brain. Only <a href="/facts/Arthropods/JKJLTFzp">arthropods</a>, <a href="/facts/Cephalopods/80GlMxHG">cephalopods</a> and <a href="/facts/Vertebrates/tT54FSTT">vertebrates</a> have a true brain, though precursor structures exist in <a href="/facts/Onychophora/CVn4wdwx">onychophorans</a>, <a href="/facts/Gastropods/rYPqm3PT">gastropods</a> and <a href="/facts/Lancelets/r1s2Ef9J">lancelets</a>.
</p><p>The rest of this article exclusively discusses the vertebrate central nervous system, which is radically distinct from all other animals.
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Central nervous system open-in-new

Central nervous system