Download Nervous System: Spine

Why have paths cross R to L in
the brain?
• scientists not sure
• possibly due to evolutionary process
Chapter 7:
The Spinal Cord
Spinal Cord
• 17 inches long
• provides 2-way conduction pathway to and
from the brain
• major reflex center
Spinal Cord
• foramen magnum to
L1 or L2
• meninges cushion
and protect
• 31 pairs of spinal
nerves
• cauda equina
Gray Matter of Spinal Cord
• central canal
• butterfly or “H” shape
• dorsal (posterior) horns
• ventral (anterior) horns
Gray Matter of Spinal Cord
• dorsal horn
– association neurons
• dorsal root
– ganglion: cell bodies of sensory neurons
• ventral horn
– cell bodies of motor neurons
• ventral root
– axons of motor neurons
White Matter of Spinal Cord
• what makes it white?
• 3 regions or columns
– posterior
• sensory (afferent) tracts
– lateral
• motor (efferent) tracts
– anterior
• motor (efferent) tracts
Damage to Spinal Cord
• spastic paralysis
• quadriplegic vs. paraplegic
Lab
• Start with sheep brain dissection.
– answer questions - pp 120-122
– Review Sheet 14 - pp 295-299
• on human brain model
– find internal and external brain structures
– trace path of CSF through human brain model
– identify cranial nerves
• if you do not finish, USE THE OPEN LABS