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CNS
• Gray matter: cell bodies and short
nonmyelinated fibers.
• White matter: contains myelinated axons that
run together in bundles called tracts.
• Meninges: membranes covering the brain and
spinal cord. (dura mater (outermost), arachinod,
pia mater (innermost)).
• The subarachinod area is full of cerebrospinal
fluid.
CNS: Spinal Cord
• Extends from the base of the brain through
the foramen magnum of the cranium.
• It is protected by the vertebral column and
is located in the vertebral foramen.
• The spinal cord ends at L1.
CNS: Spinal Cord Anatomy
• Central canal with gray matter surrounded by white
matter.
• The central canal contains cerebrospinal fluid.
• Portions of sensory and motor neurons reside in the gray
matter as do interneurons. The posterior root of a spinal
nerve enters here and the anterior root (containing motor
fibers) exits the gray matter.
• Spinal nerves are created by the joining of these two
roots (part of PNS).
• White matter is made of ascending and descending
tracts that take data to and from the brain. Because
these tracts cross just after they enter or exit the brain,
the right side of the brain controls the left side of the
body and the left side of the brain controls the right side
of the body.