{"id":4004,"date":"2017-03-27T18:24:04","date_gmt":"2017-03-27T18:24:04","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/wm-biology2\/?post_type=chapter&#038;p=4004"},"modified":"2024-04-26T02:53:38","modified_gmt":"2024-04-26T02:53:38","slug":"components-of-the-central-nervous-system","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/wm-biology2\/chapter\/components-of-the-central-nervous-system\/","title":{"raw":"Components of the Central Nervous System","rendered":"Components of the Central Nervous System"},"content":{"raw":"<div class=\"textbox learning-objectives\">\r\n<h3>Learning Outcomes<\/h3>\r\n<ul>\r\n \t<li>Identify the components of the central nervous system<\/li>\r\n<\/ul>\r\n<\/div>\r\nThe central nervous system (CNS) is made up of the brain, a part of which is shown in Figure\u00a01 and spinal cord and is covered with three layers of protective coverings called <b>meninges<\/b> (from the Greek word for membrane). The outermost layer is the <b>dura mater<\/b>(Latin for \u201chard mother\u201d). As the Latin suggests, the primary function for this thick layer is to protect the brain and spinal cord. The dura mater also contains vein-like structures that carry blood from the brain back to the heart. The middle layer is the web-like <b>arachnoid mater<\/b>. The last layer is the <b>pia mater<\/b> (Latin for \u201csoft mother\u201d), which directly contacts and covers the brain and spinal cord like plastic wrap. The space between the arachnoid and pia maters is filled with <b>cerebrospinal fluid (CSF)<\/b>. CSF is produced by a tissue called <b>choroid plexus<\/b> in fluid-filled compartments in the CNS called <b>ventricles<\/b>. The brain floats in CSF, which acts as a cushion and shock absorber and makes the brain neutrally buoyant. CSF also functions to circulate chemical substances throughout the brain and into the spinal cord.\r\n\r\nThe entire brain contains only about 8.5 tablespoons of CSF, but CSF is constantly produced in the ventricles. This creates a problem when a ventricle is blocked\u2014the CSF builds up and creates swelling and the brain is pushed against the skull. This swelling condition is called hydrocephalus (\u201cwater head\u201d) and can cause seizures, cognitive problems, and even death if a shunt is not inserted to remove the fluid and pressure.\r\n\r\n[caption id=\"attachment_2673\" align=\"aligncenter\" width=\"544\"]<img class=\"size-full wp-image-2673\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1223\/2017\/02\/07205728\/Figure_35_03_01.jpg\" alt=\"Illustration shows the three meninges that protect the brain. The outermost layer, just beneath the skull, is the dura mater. The dura mater is the thickest meninge, and blood vessels run through it. Beneath the dura mater is the arachnoid mater, and beneath this is the pia mater.\" width=\"544\" height=\"433\" \/> Figure\u00a01.\u00a0The cerebral cortex is covered by three layers of meninges: the dura, arachnoid, and pia maters. (credit: modification of work by Gray\u2019s Anatomy)[\/caption]\r\n\r\n<div class=\"textbox tryit\">\r\n<h3>Try It<\/h3>\r\nhttps:\/\/assess.lumenlearning.com\/practice\/da401141-1a6a-4ca1-bc2b-c813ddd9e259\r\n<\/div>","rendered":"<div class=\"textbox learning-objectives\">\n<h3>Learning Outcomes<\/h3>\n<ul>\n<li>Identify the components of the central nervous system<\/li>\n<\/ul>\n<\/div>\n<p>The central nervous system (CNS) is made up of the brain, a part of which is shown in Figure\u00a01 and spinal cord and is covered with three layers of protective coverings called <b>meninges<\/b> (from the Greek word for membrane). The outermost layer is the <b>dura mater<\/b>(Latin for \u201chard mother\u201d). As the Latin suggests, the primary function for this thick layer is to protect the brain and spinal cord. The dura mater also contains vein-like structures that carry blood from the brain back to the heart. The middle layer is the web-like <b>arachnoid mater<\/b>. The last layer is the <b>pia mater<\/b> (Latin for \u201csoft mother\u201d), which directly contacts and covers the brain and spinal cord like plastic wrap. The space between the arachnoid and pia maters is filled with <b>cerebrospinal fluid (CSF)<\/b>. CSF is produced by a tissue called <b>choroid plexus<\/b> in fluid-filled compartments in the CNS called <b>ventricles<\/b>. The brain floats in CSF, which acts as a cushion and shock absorber and makes the brain neutrally buoyant. CSF also functions to circulate chemical substances throughout the brain and into the spinal cord.<\/p>\n<p>The entire brain contains only about 8.5 tablespoons of CSF, but CSF is constantly produced in the ventricles. This creates a problem when a ventricle is blocked\u2014the CSF builds up and creates swelling and the brain is pushed against the skull. This swelling condition is called hydrocephalus (\u201cwater head\u201d) and can cause seizures, cognitive problems, and even death if a shunt is not inserted to remove the fluid and pressure.<\/p>\n<div id=\"attachment_2673\" style=\"width: 554px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-2673\" class=\"size-full wp-image-2673\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1223\/2017\/02\/07205728\/Figure_35_03_01.jpg\" alt=\"Illustration shows the three meninges that protect the brain. The outermost layer, just beneath the skull, is the dura mater. The dura mater is the thickest meninge, and blood vessels run through it. Beneath the dura mater is the arachnoid mater, and beneath this is the pia mater.\" width=\"544\" height=\"433\" \/><\/p>\n<p id=\"caption-attachment-2673\" class=\"wp-caption-text\">Figure\u00a01.\u00a0The cerebral cortex is covered by three layers of meninges: the dura, arachnoid, and pia maters. (credit: modification of work by Gray\u2019s Anatomy)<\/p>\n<\/div>\n<div class=\"textbox tryit\">\n<h3>Try It<\/h3>\n<p>\t<iframe id=\"assessment_practice_da401141-1a6a-4ca1-bc2b-c813ddd9e259\" class=\"resizable\" src=\"https:\/\/assess.lumenlearning.com\/practice\/da401141-1a6a-4ca1-bc2b-c813ddd9e259?iframe_resize_id=assessment_practice_id_da401141-1a6a-4ca1-bc2b-c813ddd9e259\" frameborder=\"0\" style=\"border:none;width:100%;height:100%;min-height:300px;\"><br \/>\n\t<\/iframe>\n<\/div>\n\n\t\t\t <section class=\"citations-section\" role=\"contentinfo\">\n\t\t\t <h3>Candela Citations<\/h3>\n\t\t\t\t\t <div>\n\t\t\t\t\t\t <div id=\"citation-list-4004\">\n\t\t\t\t\t\t\t <div class=\"licensing\"><div class=\"license-attribution-dropdown-subheading\">CC licensed content, Shared previously<\/div><ul class=\"citation-list\"><li>Biology 2e. <strong>Provided by<\/strong>: OpenStax. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8\">http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8<\/a>. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY: Attribution<\/a><\/em>. <strong>License Terms<\/strong>: Access for free at https:\/\/openstax.org\/books\/biology-2e\/pages\/1-introduction<\/li><\/ul><\/div>\n\t\t\t\t\t\t <\/div>\n\t\t\t\t\t <\/div>\n\t\t\t <\/section>","protected":false},"author":17,"menu_order":15,"template":"","meta":{"_candela_citation":"[{\"type\":\"cc\",\"description\":\"Biology 2e\",\"author\":\"\",\"organization\":\"OpenStax\",\"url\":\"http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8\",\"project\":\"\",\"license\":\"cc-by\",\"license_terms\":\"Access for free at https:\/\/openstax.org\/books\/biology-2e\/pages\/1-introduction\"}]","CANDELA_OUTCOMES_GUID":"c0a69180-96b3-4494-872f-8b2b2aa4ab7e, ecc6a3fd-70ba-4c12-8c9c-331b4389ac19","pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-4004","chapter","type-chapter","status-publish","hentry"],"part":3966,"_links":{"self":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapters\/4004","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/wp\/v2\/users\/17"}],"version-history":[{"count":7,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapters\/4004\/revisions"}],"predecessor-version":[{"id":8781,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapters\/4004\/revisions\/8781"}],"part":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/parts\/3966"}],"metadata":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapters\/4004\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/wp\/v2\/media?parent=4004"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapter-type?post=4004"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/wp\/v2\/contributor?post=4004"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/wp\/v2\/license?post=4004"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}