Download The Nervous System

Spinal Cord- Structure and Function
Pages 252-255
Review of nervous system terms
 Neurons = nerve cells
 Nerve cell bodies = ganglia (ganglion is singular)
 Bundles of nerve fibers:
 In the CNS = tracts
 In the PNS = nerves
Spinal Cord
 Begins at the foramen magnum of the skull
 Terminates around first or second lumbar vertebra
 conduction pathway Approaching/Exiting the brain
 Afferent vs. Efferent
 31 pairs of spinal nerves arise from the spinal cord
 Cauda equina (horse’s tail)
 a dense collection of spinal nerves at the inferior end
 Meninges cover the spinal cord
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Cervical
spinal nerves
C8
Dura and
arachnoid
mater
Thoracic
spinal nerves
T12
End of spinal cord
Lumbar
spinal nerves
Cauda equina
End of
meningeal
coverings
L5
S1
S5
Sacral
spinal nerves
Dorsal root
ganglion
White matter
Central canal
Dorsal (posterior)
horn of gray matter
Lateral horn of
gray matter
Spinal nerve
Ventral (anterior)
horn of gray matter
Dorsal root of
spinal nerve
Ventral root
of spinal nerve
Pia mater
Arachnoid mater
Dura mater
ANTERIOR
Spinal Cord Anatomy
 Gray Matter: Horns of the spinal cord
 Collection of neuron cell bodies
 Dorsal (posterior) horns (SENSORY)
house interneurons
 Receive sensory info from neurons in the dorsal root
 Anterior (ventral) horns (MOTOR)
 house somatic (voluntary) motor neurons
 Send motor information out ventral root

 White Matter: myelinated axons
 the central canal is filled with CSF
Dorsal root
ganglion
White matter
Central canal
Dorsal (posterior)
horn of gray matter
Lateral horn of
gray matter
Spinal nerve
Ventral (anterior)
horn of gray matter
Dorsal root of
spinal nerve
Ventral root
of spinal nerve
Pia mater
Arachnoid mater
Dura mater
ANTERIOR