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