InSight
T h e s p in a l c o r d
Figure 7.12
THE PLANNER^
a.
Posterior and anterior view of spinal cord
Posterior
c.
Cross-section of thoracic spinal cord
Anterior
b. Thoracic section of spinal cord
SPINAL CORD:
Gray matter
White matter
Spinal-
nerve
Central canal
SPINAL
MENINGES:
Pia mater
(inner)
Arachnoid
mater
(middle)
Dura mater
(outer)
Anterior view
through spinal cord
Cell body of motor neuron
Posterior (dorsal)
root of spinal nerve
Posterior gray horn
Posterior white column
Axon of sensory neuron
Lateral gray horn
Cell body of
sensory neuron
Anterior white column
Axon of motor neuron
Nerve impulses
for sensations
Transverse section through spinal cord
Nerve impulses to effector tissues
(muscles and glands)
Posterior (dorsal)
root ganglion
Spinal nerve
Lateral white column
Anterior (ventral) root
of spinal nerve
Central canal
Anterior gray horn
The Spinal Cord Helps the Brain
Communicate with the Environment
The spinal cord (Figure 7.12) lies in the vertebral canal
and is 42 to 45 cm (16 to 18 in.) long. It is continuous with
the medulla oblongata of the brainstem. The spinal cord
is divided into segments that correspond to the segments
of the bony vertebral column (Figure 7.12a). However,
because the spinal cord is shorter than the vertebral col-
206 CHAPTER 7
The Nervous System
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