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Alright, so now let's switch gears and talk
about the physiology of the spinal cord.
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So the purpose of the spinal
cord is to maintain homeostasis.
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And in order to do that, it must propagate
nerve impulses as well as integrate information.
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So how does information
travel in the spinal cord?
So first, let's discuss the two
main parts of the spinal cord.
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You have white matter tracts which are going to
conduct the nerve impulses to and from the brain.
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And you have gray matter tracts which
are going to receive and integrate
the incoming and outgoing information
to perform spinal reflexes.
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So let's take a closer look at how
sensory information is processed.
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First, a sensory receptor is going to detect
a sensory stimulus in a part of the body.
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Then a nerve impulse from that sensory neuron is going
to go into the spinal nerve via the posterior route.
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From this point, it can take three pathways,
two of them include sensory tracts.
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In the first sensory tract, we will send directly
into the white matter and then ascend to the brain.
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The second sensory tract involves a synapse with
an interneuron that then ascends into the brain.
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A third pathway is to synapse with an interneuron
that will then synapse with a motor neuron
in a spinal reflex pathway.
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We can also have axons that
originate from higher brain centers
and descend from the brain into the white
matter and synapse into a somatic motor neuron.
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These somatic motor neurons will
then extend to the skeletal muscles.
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Third, we have the autonomic pathway.
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In an autonomic pathway, autonomic motor
neurons are going to go to our cardiac muscles
or smooth muscles and our glands.
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These autonomic motor neurons will synapse with
other autonomic motor neurons in these effectors.