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Spinal Cord. Location Function. Meninges (for CNS). Meninx Primitiva – protective covering in fish Leptomeninx, - thin inner membrane in higher vertebrates Dura Mater – outer thick membrane in higher vertebrates. Meninges. Leptomeninx splits in mammals only, into: Pia mater – inner
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Spinal Cord • Location • Function
Meninges (for CNS) • Meninx Primitiva – protective covering in fish • Leptomeninx, - thin inner membrane in higher vertebrates • Dura Mater – outer thick membrane in higher vertebrates
Meninges • Leptomeninx splits in mammals only, into: • Pia mater – inner • Arachnoid – middle • Subarachnoid space contains Cerebrospinal fluid
Key Points • Why is meningitis a life-threatening disease?
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
Spinal Nerves • Show metamerism & carry information to & from spinal cord • Cauda equina – caudal-most set of spinal nerves resembling a horse’s tail
Spinal Nerves • Occipitospinal nerves • In anamniotes • Innervate hypobranchial muscles • Motor only
Spinal Nerves • Spinal nerves are mixed nerves with: • Dorsal root carrying sensory information • Ventral root carrying motor information
Key Points • Are spinal nerves CNS or PNS?
Spinal Nerves • Spinal nerves branch into dorsal branch supplying epaxial muscles called Dorsal Ramus • And ventral branch supplying hypaxial muscles called Ventral Ramus
Spinal Nerves • Adjacent spinal nerves for networks or plexuses when supplying limbs