Meninges the_spinal_cord


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Meninges the_spinal_cord

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