Innervation of the Abdominal Viscera

Question 1

What are the three branches of the lower splanchnic nerves that innervate the abdominal viscera (give their respective spinal levels as well)

Answer 1

Greater Splanchnic Nerve: T5-T9 Lesser Splanchnic Nerve: T10-T11 Least Splanchnic Nerve: T12

Question 2

What lower thoracic splanchnic nerve is the main source of presynaptic nerve fibers innervating the abdominal viscera?

Answer 2

Greater Splanchnic Nerve (T5-T9)

Question 3

The lower thoracic splanchnic nerves convey presynaptic sympathetic fibers to what adominal structures?

Answer 3

Celiac, Superior Mesenteric, & Prevertebral Sympathetic Ganglia

Question 4

The lumbar splanchnic nerves covey presynpatic sympathetic fibers to what abdominal structures?

Answer 4

Intermesenteric, Inferior Mesenteric, and Superior Hypogastric Plexus

Question 5

What are the two main divisions of parasympathetic innervation to the GI system?

Answer 5

1) Anterior and Posterior Vagal Trunks 2) Pelvic Splanchnic Nerves

Question 6

Anterior and Posterior Vagal Trunks: 1) Continuation of ? 2) Function ?

Answer 6

1) Right and left Vagus nerves; respectively 2) Parasympathetic innervation of the smooth muscle and glands up to the Left colic flexure

Question 7

Pelvic Splanchnic Nerves: 1) Derived from 2) Function

Answer 7

1) Anterior Rami of S2-S4 2) Parasympathetic innervation from left colic flexure to the remainder of the GI system

Question 8

Pelvic Splanchnic nerves: 1) Characteristics 2) Derived from 3) Pathway/Contribution

Answer 8

1) Not associated with sympathetic trunk 2) Derived from anterior rami of spinal nerves S2-S4 3) Presynaptic parasympathetic nerve fibers to inferior hypogastric plexus

Question 9

Enteric Nervous System:

1 &2) Two Principle Components

A) Their function

B) Sympathetic or Parasympathetic

Answer 9

1) Myenteric (Auerbach’s) Plexus A) Motility B) Parasympathetic
2) Submucosa (Meissner’s) Plexus A) Secretion/Absorption B) Sympathetic

Question 10

Nerves of Superior Mesenteric Plexus:

1) Sympathetics
2) Parasympathetics

Answer 10

1) Greater and lesser splanchnic Nerves & GVA pain fibers
2) Median root from celiac plexus, branch of posterior vagal trunk, GVA visceral reflex fibers

Question 11

Nerves of Inferior Mesenteric Plexus:

1) Sympathetic
2) Parasympathetic

Answer 11

1) Lumbar ganglia of sympathetic trunk & GVA pain fibers
2) Medial root from intermesenteric plexus (continuation of vagus), GVA reflex fibers

Question 12

Superior Hypogastric Plexus:

1) Characteristics
2) Supplies
3) Sympathetics or Parasympathetics
4) Connections

Answer 12

1) Anterior abdominal aortic bifurcation & continuous with intermesenteric and inferior mesenteric plexuses
2) Uteric and Testicular Plexues
3) Only sympathetics
4) Connected to inferior hypogastrix plexus via R/L Hypogastric nerves

Question 13

Pain Afferents are conveyed via?

Answer 13

Sympathetic components to T5-L2

Question 14

Reflex Afferents (information from chemoreceptors, osmoreceptors, and mechanoreceptors); these are conveyed to?

Answer 14

Autonomic centers in the medulla oblongata

Question 15

Inferior Hyopgastric Plexus:

1) Sympathetics
2) Parasympathetics
3) Output

Answer 15

1) Superior Sacral Sympathetics
2) Pelvic Splanchnics (S2-S4)
3) Visceral plexuses on walls of pelvic viscera