1. Spinal Cord
Location
Function

3. Meninges (for CNS) Meninx Primitiva – protective covering in fish
Leptomeninx, - thin inner membrane in higher vertebrates
Dura Mater – outer thick membrane in higher vertebrates

4. Meninges Leptomeninx splits in mammals only, into: Pia mater – inner
Arachnoid – middle
Subarachnoid space contains Cerebrospinal fluid

6. Key Points
Why is meningitis a life-threatening disease?

7. Spinal cord
Gray matter contains nuclei, nonmyelinated neurons, at center of spinal cord
White matter contains myelinated ascending and descending tracts, at peripheral spinal cord

9. Spinal Nerves
Show metamerism & carry information to & from spinal cord
Cauda equina – caudal-most set of spinal nerves resembling a horse’s tail

11. Spinal Nerves Occipitospinal nerves In anamniotes
Innervate hypobranchial muscles
Motor only

12. Spinal Nerves Spinal nerves are mixed nerves with:
Dorsal root carrying sensory information
Ventral root carrying motor information

14. Key Points
Are spinal nerves CNS or PNS?

15. Spinal Nerves
Spinal nerves branch into dorsal branch supplying epaxial muscles called Dorsal Ramus
And ventral branch supplying hypaxial muscles called Ventral Ramus

16. Spinal Nerves
Adjacent spinal nerves for networks or plexuses when supplying limbs