Abdomen - Nervous System 2

on 24.6.07 with 0 comments



Feature

SYMPATHETIC

PARASYMPATHETIC

Spinal Chord Origin

Thoracolumbar: T5-T12, L1-L2

Craniosacral: C10 (Vagus Nerve), S2-S4.

Effects

Widespread

low precision Specific, discrete, local, acute.

Location of cell bodies

Along the spinal chord, at the sympathetic chain ganglia.

Adjacent to or in the target organ.

Pre Ganglionic Fibers

Short

Long

Post-Ganglionic

Long

Short


The Vagus Nerve: Foregut and Midgut innervation

  • In the thorax, the right vagus runs posterior to the esophagus, and the left vagus runs anterior to it.
  • Around the esophageal hiatus (T10), the two vagus nerves mix, and then they separate again, to form the right and left vagal trunks.
    • Left (Anterior) Vagal Trunk: Gives off Hepatic Branch and Principle Anterior Gastric Branch.
    • Right (Posterior) Trunk: Forms the Celiac Plexus ------> Superior Mesenteric Plexus.
    • These nerves are perivascular -- they follow the course of the arteries.

Pelvic Splanchnic Nerves: Hindgut innervation

  • The Pelvic Splanchnic Nerves are parasympathetic Sacral spinal nerves S2-S4.
  • They form Pelvic Plexuses ------> Inferior Hypogastric Plexus ------> Pelvic viscera, and separately, the hindgut.
  • These nerves are Non-Perivascular. They do not follow the arteries, but instead crisscross the arteries. The nerves are still located in mesentery.
  • The lower anus (below pectinate line) is innervated by somatic nerves -- the pudendal nerve -- not parasympathetic pelvic splanchnic.
  • Greater Thoracic Splanchnics: T6-T9, Sympathetic spinal nerves supplying the foregut and midgut.
  • Lesser Thoracic Splanchnic: T10-T11, Sympathetic spinal nerves supplying the hindgut, generally.
  • Least Thoracic Splanchnic: T12. It supplies the Renal Plexus.

Category: Anatomy Notes

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