Parasympathetic Nervous System (PNS): Organization

by James Pickering, PhD

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    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.

    About the Lecture

    The lecture Parasympathetic Nervous System (PNS): Organization by James Pickering, PhD is from the course Lymphatics and Nerves of Abdominopelvic Region.

    Included Quiz Questions

    1. The preganglionic nerve fibers are longer than the postganglionic nerve fibers.
    2. The vagus nerve is cranial nerve IX.
    3. The myenteric plexus is located in the thorax.
    4. The parasympathetic nervous system innervates only hair follicles and sweat glands.
    1. Cranial
    2. Sacral
    3. Thoracic
    4. Lumbar
    5. Cervical

    Author of lecture Parasympathetic Nervous System (PNS): Organization

     James Pickering, PhD

    James Pickering, PhD

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