What Is the Spinal Cord?

What Is the Spinal Cord?
The spinal cord extends from the brain and serves mostly as a relay
station connecting the brain to the rest of the body. For protection, the
human spinal cord is encased by bony vertebrae. The region of the spinal
cord closest to the brain connects the brain to regions of the body in that
proximity. This would include the chest and arms. Moving further down
the spinal cord and away from the brain, you begin to find the intercon-
nections between the central nervous system and the lower portions of
our body, such as our legs. However, because the nerve links extending
from the lower extremities must move through the upper regions of the
spinal cord in order to connect with the brain, damage to the upper
region of the spinal cord will affect the lower as well as the upper areas
of our body. Thus, if damage occurs lower in the spinal cord it may result
in temporary or permanent paralysis of only the lower extremities.
However, if the spinal cord is damaged higher up, it can result in paralysis
of both lower and upper extremities.
   When you would like to move a particular body part, the process (idea)
originates in the brain in a region called the motor cortex. Motor means
movement! Once initiated, the impulse is carried along a linkage of nerve
cells to the skeletal muscle responsible for moving the limb or body part
that is to move. Incredibly the whole process only requires a couple
neurons linked in series connecting the motor cortex of the brain to the
muscle and occurs in a fraction of a second.
   While the motor cortex of our brain is busy sending signals to our
skeletal muscle, signaling it to move, another region of our brain is evalu-
ating and refining the movement. This region is called the cerebellum,
which is behind and lower than the more recognizable parts of the brain.
It is also this region of the brain that is particularly sensitive to the effects
of alcohol and explains why movement becomes less refined when we are
intoxicated.