Central Nervous System

The <span style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-weight: 700; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline;">central nervous system (<span style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-weight: 700; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline;">CNS) is the part of the <a href="https://en.wikipedia.org/wiki/Nervous_system" title="Nervous system" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161);">nervous system</a> consisting of the <a href="https://en.wikipedia.org/wiki/Brain" title="Brain" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161);">brain</a>and <a href="https://en.wikipedia.org/wiki/Spinal_cord" title="Spinal cord" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161);">spinal cord</a>. The CNS is so named because it integrates the received information and coordinates and influences the activity of all parts of the bodies of <a href="https://en.wikipedia.org/wiki/Bilaterian" title="Bilaterian" class="mw-redirect" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161);">bilaterally symmetric animals</a>—that is, all multicellular animals except <a href="https://en.wikipedia.org/wiki/Sponge" title="Sponge" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161);">sponges</a> and <a href="https://en.wikipedia.org/wiki/Radiata" title="Radiata" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161);">radially symmetric animals</a> such as <a href="https://en.wikipedia.org/wiki/Jellyfish" title="Jellyfish" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161);">jellyfish</a>—and it contains the majority of the nervous system. Many consider the <a href="https://en.wikipedia.org/wiki/Retina" title="Retina" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161);">retina</a><span class="mw-ref" id="cite_ref-Purves_2000_2-0" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; font-size: 0.75em; line-height: 1; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: super; unicode-bidi: embed;"><a href="https://en.wikipedia.org/#cite_note-Purves_2000-2" style="margin: 0px; padding: 0px; border: 0px; font: inherit; vertical-align: baseline; color: rgb(107, 75, 161); counter-reset: mw-Ref 2;"></a> and the <a href="https://en.wikipedia.org/wiki/Optic_nerve" title="Optic nerve" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161);">optic nerve</a>(<a href="https://en.wikipedia.org/wiki/Cranial_nerve" title="Cranial nerve" class="mw-redirect" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161);">cranial nerve</a> II),<span class="mw-ref" id="cite_ref-3" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; font-size: 0.75em; line-height: 1; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: super; unicode-bidi: embed;"><a href="https://en.wikipedia.org/#cite_note-3" style="margin: 0px; padding: 0px; border: 0px; font: inherit; vertical-align: baseline; color: rgb(107, 75, 161); counter-reset: mw-Ref 3;"></a><span class="mw-ref" id="cite_ref-Fitzgerald_4-0" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; font-size: 0.75em; line-height: 1; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: super; unicode-bidi: embed;"><a href="https://en.wikipedia.org/#cite_note-Fitzgerald-4" style="margin: 0px; padding: 0px; border: 0px; font: inherit; vertical-align: baseline; color: rgb(107, 75, 161); counter-reset: mw-Ref 4;"></a> as well as the <a href="https://en.wikipedia.org/wiki/Olfactory_nerves" title="Olfactory nerves" class="mw-redirect" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161);">olfactory nerves</a> (cranial nerve I) and <a href="https://en.wikipedia.org/wiki/Olfactory_epithelium" title="Olfactory epithelium" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161);">olfactory epithelium</a><span class="mw-ref" id="cite_ref-Gizurarson_S.2012_566–582_5-0" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; font-size: 0.75em; line-height: 1; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: super; unicode-bidi: embed;"><a href="https://en.wikipedia.org/#cite_note-Gizurarson_S.2012_566%E2%80%93582-5" style="margin: 0px; padding: 0px; border: 0px; font: inherit; vertical-align: baseline; color: rgb(107, 75, 161); counter-reset: mw-Ref 5;"></a> as parts of the CNS, synapsing directly on brain tissue without intermediate <a href="https://en.wikipedia.org/wiki/Ganglion" title="Ganglion" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161);">ganglia</a>. As such, the <a href="https://en.wikipedia.org/wiki/Olfactory_epithelium" title="Olfactory epithelium" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161);">olfactory epithelium</a> is the only central nervous tissue in direct contact with the environment, which opens up for <a href="https://en.wikipedia.org/wiki/Therapeutic" title="Therapeutic" class="mw-redirect" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161);">therapeutic</a> treatments. <span class="mw-ref" id="cite_ref-Gizurarson_S.2012_566–582_5-1" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; font-size: 0.75em; line-height: 1; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: super; unicode-bidi: embed;"><a href="https://en.wikipedia.org/#cite_note-Gizurarson_S.2012_566%E2%80%93582-5" style="margin: 0px; padding: 0px; border: 0px; font: inherit; vertical-align: baseline; color: rgb(107, 75, 161); counter-reset: mw-Ref 5;"></a> The CNS is contained within the <a href="https://en.wikipedia.org/wiki/Dorsal_body_cavity" title="Dorsal body cavity" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161);">dorsal body cavity</a>, with the <a href="https://en.wikipedia.org/wiki/Brain" title="Brain" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161);">brain</a> housed in the <a href="https://en.wikipedia.org/wiki/Cranial_cavity" title="Cranial cavity" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161);">cranial cavity</a> and the spinal cord in the <a href="https://en.wikipedia.org/wiki/Spinal_canal" title="Spinal canal" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161);">spinal canal</a>. In vertebrates, the brain is protected by the <a href="https://en.wikipedia.org/wiki/Skull" title="Skull" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161);">skull</a>, while the spinal cord is protected by the <a href="https://en.wikipedia.org/wiki/Vertebrae" title="Vertebrae" class="mw-redirect" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161);">vertebrae</a>.<span class="mw-ref" id="cite_ref-Maton_6-0" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; font-size: 0.75em; line-height: 1; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: super; unicode-bidi: embed;"><a href="https://en.wikipedia.org/#cite_note-Maton-6" style="margin: 0px; padding: 0px; border: 0px; font: inherit; vertical-align: baseline; color: rgb(107, 75, 161); counter-reset: mw-Ref 6;"></a>The brain and spinal cord are both enclosed in the <a href="https://en.wikipedia.org/wiki/Meninges" title="Meninges" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161);">meninges</a>.<span class="mw-ref" id="cite_ref-Maton_6-1" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; font-size: 0.75em; line-height: 1; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: super; unicode-bidi: embed;"><a href="https://en.wikipedia.org/#cite_note-Maton-6" style="margin: 0px; padding: 0px; border: 0px; font: inherit; vertical-align: baseline; color: rgb(107, 75, 161); counter-reset: mw-Ref 6;"></a> Within the CNS, the interneuronal space is filled with a large amount of supporting non-nervous cells called neuroglial cells.