Spinal cord development, CSF pathways and blood supply

Card Set Information

Spinal cord development, CSF pathways and blood supply
2015-01-17 06:35:51
Spinal cord CSF anatomy

Vet Med - Module 8
Show Answers:

  1. During neurulation the notochord induces overlaying ectoderm to become ...?  And for a ...?
    neuroectoderm, neural tube
  2. What are the stages of neural tube formation?
    • A neural plate forms (overlying ectoderm becomes a thickened neural plate)
    • This becomes the a neural groove
    • The dorsal margins of the neural groove merge medially forming a neural tube composed of neuroepithelial cells surrounding a neural cavity
  3. The neural tube becomes the CNS/PNS?
    CNS, which consists of the brain and spinal cord
  4. What does the cavity of the neural tube become?
    The ventricles of the brain and central canal of the spinal cord
  5. What becomes the cells of the PNS?
    The neural crest cells
  6. What are enlargements of spinal cord segments that innervate the limbs a result of?
    Greater numbers of neurones in these segments due to less neuronal degeneration compared to segments that do not innervate limbs
  7. Describe the formation of the meninges and the subarachnoid space
    The mesenchyme surrounding the neural tube aggregates into two layers. The outer layer forms the dura mater. The cavities develop and coalesce within the inner layer, dividing it into arachnoid and pia mater.  The cavity becomes the subarachnoid space which contains CSF.
  8. What do the dorsal grey column, intermediate grey column and ventral grey column of the spinal cord develop into?
    • Dorsal grey column - sensory neurones
    • Intermediate grey column - autonomic nervous system
    • Ventral grey column - motor neurones
  9. Describe the development of dorsal nerve roots
    Axons energy from the segmental spinal ganglions (neural crest) and grow into the alar plate (dorsal horn of the neural tube)
  10. Where are cell bodies of dorsal nerve roots located?
    They are located in the spinal ganglion
  11. What do dorsal nerve roots form?
    Afferent (sensory) neurones
  12. Describe the development of ventral nerve roots
    Axons grow from the basal plate (ventral horn of the neural tube) out of the neural tube
  13. Where are ventral nerve root cell bodies located?
    In the spinal cord
  14. What structure is the remnants of the notochord?
    The nucleus pulposus of intervertebral discs
  15. List the ventricles present in the brain
    Lateral, 3rd and 4th ventricles
  16. What structure does the 3rd ventricle surround?
    The interthalamic adhesion
  17. CSF passes from the 3rd ventricle through the ... to get to the 4th ventricle?
    Mesencephalic aquaduct
  18. Where is CSF ultimately drained away through?
    The dorsal sagittal sinus
  19. How does CSF get into the subarachnoid space between the spinal cord and dura?
    Through the lateral aperture
  20. What structures produce CSF?
    The choroid plexus of the lateral, 3rd and 4th ventricles
  21. Describe cervical collection of CSF
    The animal must be under anaesthesia.  The neck is flexed and the needle inserted midline between C1 and C2.  Stop advancing the needle when you enter the CSF space.
  22. Describe lumbar collection of CSF
    The animal is restrained.  The needle is advanced to the floor f the spinal canal and withdrawn.  The position of the lumbar tap varies between species depending on the caudal extent of the spin cord.  It is ~L6.
  23. What would a very turbid looking sample of CSF reflect?
    A high cell count
  24. What is a problem with lumbar taps?
    They are more likely to be 'dry', especially in small fat patients or cats
  25. Describe the arterial blood supply to the spinal cord
    Lumbar arteries of the aorta, intercostal arteries and vertebral arteries --> paired spinal arteries ---> dorsal and ventral root artery per spinal cord segment ---> superficial and anastomosing arteries of the spinal cord ---> deep arteries in the spinal cord leading to 3 vascular zones
  26. What are the three vascular zones in the spinal cord?
    • Inner vascular zone - vertical arteries only
    • Middle vascular zone - both vertical and radial arteries
    • Outer vascular zone - radial arteries only
  27. Describe the venous drainage of the spinal cord
    Ventral spinal vein (drains spinal cord) ---> vertebral venous sinus ---> segmental spinal veins ---> vertebral veins, azygous vein and caudal vena cava ---> systemic circulation
  28. Which vessel does the ventral spinous vein escort along in the ventral fissure of the spinal cord?
    The ventral spinal artery
  29. True or false: the vertebral venous sinuses have valves?
    False - they are valveless
  30. What is the significance of these sinuses being valveless?
    Some infections can use these areas for transport as blood can move backwards and forwards freely.
  31. Where are the vertebral venous sinuses located?
    In the epidural space longitudinal on the floor of the vertebral canal