Skip to main content
Chemistry LibreTexts

The Central

  • Page ID
  • The central nervous system (CNS) is made up of the brain and spinal cord and is covered with three layers of protective coverings called meninges (“meninges” is derived from the Greek and means “membranes”) (Figure). The outermost layer is the dura mater, the middle layer is the web-like arachnoid mater, and the inner layer is the pia mater, which directly contacts and covers the brain and spinal cord. The space between the arachnoid and pia maters is filled with cerebrospinal fluid (CSF). The brain floats in CSF, which acts as a cushion and shock absorber.

    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 meninx, and blood vessels run through it. Beneath the dura mater is the arachnoid mater, and beneath this is the pia mater. The cerebral cortex is covered by three layers of meninges: the dura, arachnoid, and pia maters. (credit: modification of work by Gray's Anatomy)

    Complete the tasks on the list below:

    • Go to this page,, scroll down the page to the section titled, The Central Nervous System, and read from there to the bottom of the page
    • The QR codes on the page that link to the following, be sure to take the time to visit each link below, or use the QR codes on the page.
    • Use the Glossary at the bottom of the page to help with the vocabulary for this week
    • Use the Review Questions and Free Response questions to check for understanding

    Download for free at