Nerves of the Abdomen

Question 1

In general, what type of nerves supply the body wall, diaphragm and parietal peritoneum?

Answer 1

somatic nerves

Question 2

In general, what type of nerves supply the visceral part of the abdomen?

Answer 2

autonomic nerves with both motor and sensroy componetns

Question 3

THe sympathetic autonomic fibers are assotiated with what spinal cord segments?

Answer 3

T1-L2

Question 4

Parasympathetic autnomic fibers are associated with what spinal cord segments?

Answer 4

brain stem cranial nerves and spinal cord segments S2-S4

Question 5

What are the general functions of the sympathetic nervous system in the GI system?

Answer 5

inhibit peristalsis

vasoconstriction to divert blood away

Question 6

What are the general functions of the parasympathetic nervous system in the GI tract?

Answer 6

stimualtes peristalsis, relaxes sphincters and stimulates glandular secretion

Question 7

What two sets of splanchnics have sympathetic nerves?

Answer 7

thoracic splanchnics

lumbar splanchnics

Question 8

What are the three thoracic splanchnics?

Answer 8

greater splanchnic
lesser splanchnic
least splanchnic

Question 9

Are the fibers in the thoracic splanchnics preganglionic or postganglionic?

Answer 9

preganglionic - from T5-T12

they pass through the sympathetic trunk WITHOUT synapsing to travel to the prevertebral ganglia/plexuses

Question 10

How many lumbar splanchnics ar ethere?

Answer 10

4 pairs, so 8

Question 11

The preganglionic sympathetic branches of the lumbar splanchnics leave the sympathetic trunk at what levels?

Answer 11

L1-L4

Question 12

The symapthetic outflow ends at what level?

Answer 12

L2 spinal chord level

Question 13

So the lumbar sympathetics that exit from L3 and L4 are actually from what?

Answer 13

L1-L2 levels

Question 14

What two plexuses do most of the lumbar splanchnic nerves join?

Answer 14

intermesenteric and inferior mesenteric plexuses

just some go to the superior hypogastric plexus as well

Question 15

What are the parasympathetic nerves of the GI system?

Answer 15

the vagus and the pelvic splanchnic nerves

Question 16

What levels do the pelvic splanchnics come off?

Answer 16

S2-S4

Question 17

THe preganglionic parasympathetic fibers exit from S2-4 and then ascend into the abdomen via what plexuses?

Answer 17

the hypogastric plexuses

Question 18

Where do the preganglionic parasympathetics from the hypogastric plexuses synapse? Aka…what part of the GI system gets parasympathetics from the pelvic splanchnics instead of the vagus?

Answer 18

onto postganglionic parasymapthetic fibers in the walls of organs DISTAL to the left colic flexure

so basically the hindgut

Question 19

True or false: most preganglionic parasympathetic fibers do not synapse in the prevertebral ganglia an dinstead pass thorugh the plexuses to follow arteries to the wall of the gut.

Answer 19

true

Question 20

What part of the GI system gets its parasymapthetics from the vagus?

Answer 20

anything proximal to the left colic flexure - so foregut and midgut

Question 21

The posterior vagal trunk has a large branch that brings preganglionic parasympathetic fibers to the celiac and superior mesneteric plexuses. What’s it called?

Answer 21

the celiac branch

Question 22

As mentioned before, the visceral afferent sensory fibers are in the sympathetic nerves. THey travel in the splanchnic nerves to dorsal root ganglia at what levels of the spinal cord?

Answer 22

T1-L2

this is why visceral sensation is dull and vague compared to somatic pain - the info is received by too many levels for accurate localization

Question 23

Describe how referred pain works in the abdomen?

Answer 23

spinal cord segments receive both somatic AND visceral sensory input that converge on a relatively limited number of second order neurons

thus, visceral pain is often referred to the somatic tissue supplied by the same cord segment

Question 24

THe visceral sensory nerves going in the parasympathetic fibers PROXIMAL to the L colic flexur will course to what sensory ganlion?

Answer 24

the nodose or sensory ganglion of the vagus

because the vagus supplies proximal to the left colic flexure

Question 25

The visceral sensory nerves going in the parasympathetic fibers DISTAL to the left colic flexure will course to what sensory gnaglia?

Answer 25

the dorsal root ganglia of S2-4 in the pelvic splanchnic nerves

Question 26

The celiac ganglion around the celiac trunk receives what two sets of splanhcnic nerves?

Answer 26

greater and lesser splanchnic (sympathetic)

Question 27

What offshoot of the celiac gnaglion will receive the lesser splanchnic?

Answer 27

the aorticorenal plexus

Question 28

Will the vagal preganglionic parasympathetics synapse in the celiac ganglion?

Answer 28

nope - just pass through

Question 29

What splanchnics are received by the superior, inferior and intermestneric ganglia/plexi?

Answer 29

the upper two lumbar splanchnics L1 and L2 synapse there while vagal fibers pass through the superior mesenteric (only)

Question 30

At what level does the superior hypogastric plexus lie/

Answer 30

at the level of the bifurcation of the aorta (L5)

Question 31

What splanchnics are received by the superior hypogastric plexus?

Answer 31

preganglionic sympathetic fibers from the L3 and L4 splanchnic nervees

Question 32

What does the superior hypogastric plexus divide into?

Answer 32

the rigth and lleft hypogastric nerves that descend into the pelvis to contribute to the inferior hypogastric plexus

Question 33

What preganglionic parasympathetic fibers pass thorugh the superior hypogastric plexus to contrinue to the organ supplied?

Answer 33

the pelvic splanchnic nerves from S2-4