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  • 1. Meninges & The Spinal Cord Chapter 9: Nervous System Unit 3: Integration and Coordination
  • 2. Meninges
    • Bones, membranes, and fluid surround the organs of the CNS.
      • Layered membranes called Meninges lie between these bony coverings and the soft tissues of the CNS.
        • The meninges serve as protection for the brain and the spinal cord
  • 3. Layers of the Meninges
    • Meninges have three layers:
      • Dura Mater
        • The outermost layer of the meninges
      • Arachnoid Mater
        • The middle layer of the meninges
      • Pia Mater
        • The innermost layer of the meninges
  • 4.
  • 5. Dura Mater
    • Dura mater is composed primarily of tough, white, fibrous connective tissue.
      • Contains many blood vessels and nerves.
        • Attached to the interior portion of the skull and serves as the periosteum for the inside of the cranium.
        • Also extends inward between the lobes of the brain (partitions and protection)
  • 6. More on Dura Mater
    • Dura mater extends from the cranium into the vertebral canal.
      • It is a strong tubular sheath that surrounds the spinal cord.
        • It is not attached to the vertebrae spinal cord, but is separated by a space called the Epidural Space
  • 7.
  • 8.
  • 9. Arachnoid Mater
    • The Arachnoid Mater is a thin, web-like membrane without blood vessels
      • Lies between the dura mater and the pia mater
      • It spreads over the brain and the spinal cord
  • 10.
  • 11. Pia Mater
    • The Pia Mater is very thin and delicate.
    • Contains many blood vessels that nourish the cells of the brain and the spinal cord.
      • This layer is connected to the surfaces of both the brain and the spinal cord.
        • Separating the pia mater from the arachnoid mater is the Subarachnoid Space .
          • This space contains the clear, watering Cerebrospinal Fluid (CSF)
  • 12.
  • 13. The Spinal Cord
    • The Spinal Cord is a slender nerve column that passes downward from the brain into the vertebral canal.
      • This structure is continuous with the brain, but officially begins where nervous tissue leaves the cranial cavity (foramen magnum).
  • 14.
  • 15. Structure of the Spinal Cord
    • The spinal cord consists of 31 segments that each give rise to a pair of spinal nerves.
      • Spinal nerves branch to different parts to connect the CNS to the PNS.
      • There are two spinal nerves that arise between every vertebraeone to each side of the body
      • Various parts of the spinal cord supply nerves to specific parts of the PNS.
  • 16.
  • 17. Spinal Cord Enlargements
    • The Cervical Enlargement is found in the neck region of the spinal cord.
      • Supplies nerves to the upper limbs
    • The Lumbar Enlargement is found in the lower back region of the spinal cord.
      • Supplies nerves to the lower limbs
  • 18.
  • 19. Spinal Cord Anatomy
    • The human spinal cord has a very distinct appearance when viewed in cross section
    • The spinal cord is segmented
      • One segment per vertebra
      • Each segment is nearly identical to all other segments
  • 20. Spinal Cord Anatomy
  • 21. Spinal Cord Anatomy
    • The spinal cord has both grey matter & white matter
      • White matter is composed of myelinated neuronal axons
      • Grey matter is unmyelinated
        • Made mostly of neuron cell bodies
        • Makes up the central region of the spinal cord
        • Looks somewhat like a butterfly
  • 22. Spinal Cord Anatomy
    • The Grey Matter Butterfly
      • The top of the butterfly is toward the posterior
      • The bottom of the butterfly toward anterior
      • The wings are called horns
        • posterior horn
        • anterior horn
  • 23. Spinal Cord Anatomy
  • 24. Spinal Cord Anatomy
    • The anterior horns give rise to anterior roots
      • The anterior roots are composed of the axons of motor neurons
      • The axons of the anterior horn/root join up with the axons of the posterior root to form a spinal nerve
  • 25. Spinal Cord Anatomy
    • The posterior horn gives rise to posterior roots
      • These roots are made of the axons of sensory neurons
      • Usually, there are ganglia associated with the posterior roots
        • Ganglia (singular: ganglion ) are clumps of nerve cell bodies that allow neurons to communicate