00:01
Now, let's look at the organization
of the parasympathetic
nervous system.
00:06
And remember, this is characterized
by incredibly long
preganglionic fibers
that go all the way
to the target organ.
00:14
Then within the target organ,
they have very short
postganglionic fibers.
00:20
So here we can see the
dorsal nucleus of the vagus nerve.
00:22
And this gives rise to the key
parasympathetic nerve of the body.
00:27
The vagus nerve, cranial nerve 10.
00:30
So here we have the
vagal nerve leaving the brainstem
and it passes all the way down
the thorax through the diaphragm,
and it's giving rise to a
long preganglionic plexus.
00:41
Once this preganglionic nerve
has given rise
to the postganglionic nerve,
this is forming that
myenteric plexus
within the muscle wall.
00:50
So, a network of nerve fibers
within the actual
muscular wall of the GI tract.
00:56
This then leads on to what's known
as the enteric nervous system.
01:00
And that's the deep
neural structure of the GI tract.
01:03
We don't need to worry
too much about it right now.
01:06
But essentially passing towards
the foregut and the midgut regions,
we have a whole series
of myenteric plexus
is associated of
all of these organs.
01:17
And they're formed via
the long preganglionic nerves
that sit in the vagus nerve.
01:23
The pelvis and the hindgut aspect
and mostly controlled
by the sacral part.
01:29
Remember, is the
cranial sacral outflow,
that is parasympathetic in nature.
01:33
And these gives rise
via the lateral horns
to pelvic splanchnic nerves.
01:39
These leave from the
sacral aspects of the spinal cord
and give rise to long
preganglionic fibers,
then they will again
form their plexus
around the target organ.
01:51
Organization of the
parasympathetic nerve.
01:54
So, we have the cranial part,
the parasympathetic nuclei
leaving the brainstem
that's going to go and innovate
in the head and neck region.
02:02
The vagus nerve specifically
is going to the liver,
the gallbladder, etc.
02:07
All the way up to the last
two thirds of the transverse,
the first two thirds of
the transverse colon.
02:14
Because the sacral part via
the pelvic splanchnic nerves
is going to supply the hindgut.
02:19
So the last third of
the transverse colon
descending sigmoid rectum,
and the pelvic organs
via these pelvic splanchnic nerves.
The lecture Parasympathetic Nervous System (PNS): Organization by James Pickering, PhD is from the course Lymphatics and Nerves of Abdominopelvic Region.
Which statement is correct about the parasympathetic nervous system?
Which regions contribute to the parasympathetic nervous system? Select all that apply.
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