13-1 The Spinal Cord & Spinal Nerves • Together with brain forms the CNS • Functions – spinal cord reflexes – integration (summation of inhibitory and excitatory) nerve impulses – highway for upward and downward travel of sensory and motor information
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Protection Of The Spinal Cord 12 CNS.pdf · •Integration center for spinal reflexes is gray matter of spinal cord •Examples –somatic reflexes result in skeletal muscle contraction
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13-1
The Spinal Cord & Spinal Nerves
• Together with brain forms the CNS
• Functions
– spinal cord reflexes
– integration (summation of inhibitory and
excitatory) nerve impulses
– highway for upward and downward travel of
sensory and motor information
13-2
Spinal Cord Protection
By the vertebral column, meninges, cerebrospinal fluid, and vertebral ligaments.
13-3
Structures Covering the Spinal Cord
• Vertebrae
• Epidural space filled with fat
• Dura mater
– dense irregular CT tube
• Subdural space filled with
interstitial fluid
• Arachnoid = spider web of
collagen fibers
• Subarachnoid space = CSF
• Pia mater
13-4
External Anatomy of Spinal Cord
• Flattened cylinder
• 16-18 Inches long &
3/4 inch diameter
• In adult ends at L2
• In newborn ends at L4
• Growth of cord stops at
age 5
• Cervical enlargement
– upper limbs
• Lumbar enlargement
– lower limbs
13-5
Inferior End of
Spinal Cord
• Conus medullaris
– cone-shaped end of spinal cord
• Caudae equinae (horse’s tail)
– dorsal & ventral roots of lowest
spinal nerves
13-6
Spinal Cord & Spinal Nerves
• Spinal nerves begin as roots
• Dorsal or posterior root is incoming sensory fibers