Ach: Nerves of the Abdomen

Question 1

What are the two types of nerves found in the abdomen and pelvis?

Answer 1

Somatic (phrenic)

Autonomic (motor and sensory)

Question 2

What are the two anatomical divisions of the nerves that supply the abdomen and pelvis?

Answer 2

Sympathetic (T1-L2)

Parasympathetic (brain stem and spinal cord segments S2-S4)

Question 3

sympathetics

Answer 3

INHIBIT peristalsis and vasoconstrict

Question 4

parasympathetics

Answer 4

STIMULATE peristalsis, relax sphincters, stimulate glandular secretion

Question 5

What makes up the visceral efferent nerves?

Answer 5

1. sympathetic nerves (T1-L2)

2. parasympathetic nerves (CN X, S2, S3, S4)

Question 6

What are the two types of visceral efferent sympathetic nerves that serve the abdomen and pelvis?

Answer 6

1. thoracic splanchnics

2. lumbar splanchnics

Question 7

thoracic splanchnics

Answer 7

PREganglionic sympathetic fibers from T5-T12 of the spinal cord that pass through the sympathetic trunk w/out synapsing and travel to prevertebral ganglia/plexuses

greater splanchnic (T5-T9)
lesser splanchnic (T10-11)
Least splanchnic (T12)

Question 8

lumbar splanchnics

Answer 8

PREganglionic sympathetic branches

exit from lumbar sympathetic trunk at L1-L4

Question 9

Where does the sympathetic outflow end?

Answer 9

L2 spinal cord level

Question 10

Where do the lumbar splanchnic nerves from L1-L2 spinal cord exit?

Answer 10

travel down the sympathetic trunk and exit at L3 and L4 and synapse in prevertebral ganglia and plexuses.

Question 11

What are the two types of visceral efferent parasympathetic nerves?

Answer 11

1. Vagus nerves

2. Pelfvic splanchnic nerves (S2-4)

Question 12

Vagus nerve (parasympathetic visceral efferent)

Answer 12

Supply organs PROXIMAL to left colic flexure (foregut and midgut)

PREganglionic parasympathetic that DO NOT SYNAPSE in prevertebral ganglia, pass through plexuses and follow arteries to the wall

Question 13

Pelvic splanchnics (parasympathetic visceral efferent)
exit?

Answer 13

Organs DISTAL to left colic flexure (hindgut)

PREgang exit from S2-4 spinal cord levels>
ascend to abdomen via hypogastric plexuses>
synapse on POSTgang fibers in organs distal to left colic flexure

Question 14

What are the two types of visceral afferent fibers?

Answer 14

Sympathetic and parasympathetic

Question 15

Sympathetic visceral afferent fibers: path

Answer 15

Viscera> splanchnic nerves> dorsal root ganglia at T1-L2 of the spinal cord

Question 16

Sympathetic visceral afferent fibers: carry?

Answer 16

sensory information

visceral pain from organs to CNS (dull and vague)

Question 17

What is referred pain?

Answer 17

spinal cord segments receive both somatic and visceral sensory input that converges on second order neurons.

visceral pain is experienced in somatic tissues supplied by the same cord segment

Question 18

Parasympathetic visceral afferent nerves: proximal vs distal to L colic flexure

Answer 18

Proximal: Fibers> sensory ganglion of the VAGUS

Distal: fibers: dorsal root ganglia S2-S4 in the PELVIC SPLANCHNIC NERVES

Question 19

Parasympathetic visceral afferent nerves: function?

Answer 19

provide sensory limb for homeostatic reflexes and pain sensation from some pelvic organs

Question 20

Where do preganglionic sympathetic fibers of thoracic and lumbar splanchnic nerves synapse?

Answer 20

ganglia

Question 21

Where are postganglionic sympathetic fibers located?

Answer 21

fibers follow blood vessels to the organ they supply

Question 22

Where are preganglionic parasympathetic fibers located?

Answer 22

pass THROUGH plexuses and DO NOT SYNAPSE.

follow arteries to a specific portion of the gut>
snapse on postganglionic parasympathetic neurons in the muscular wall

Question 23

Celiac ganglion/plexus: location?

Answer 23

encircles the celiac trunk

Question 24

Celiac ganglion/plexus: receive?

Answer 24

greater and lesser splanchnic nerves (sympathetic) that synapse there

Question 25

Celiac ganglion/plexus: offshoots?

Answer 25

aorticorenal plexus (receives the lesser splanchnic)

Question 26

Celiac ganglion/plexus: what passes through w/out synapsing?

Answer 26

vagal preganglionic parasympathetis

Question 27

superior and inferior mesenteric ganglia/plexus and intermesenteric plexus: location?

Answer 27

On the AORTA surrounding the SMA and IMA

plexus extends btwn the SMA and IMA

Question 28

superior and inferior mesenteric ganglia/plexus and intermesenteric plexus: synapses here?

Answer 28

upper two lumbar splanchnics (L1,2)

Question 29

superior mesenteric plexus: passes through?

Answer 29

vagal fibers

Question 30

Is there vagal input to the intermesenteric or inferior mesenteric plexuses?

Answer 30

NO –vagus supplies parasympathetics to the foregut and midgut ONLY

Question 31

superior hypogastric plexus: locate?

Answer 31

level of bifurcation of hte aorta L5

Question 32

superior hypogastric plexus: receives?

Answer 32

PREgang sympathetic fibers from L3/4 splanchnic nerves

Question 33

superior hypogastric plexus: divides into?

Answer 33

R and L hypogastric nerves that descend into the pelvis and contribute to the IHP

Question 34

superior hypogastric plexus: what passes through and doesn’t synapse?

Answer 34

Preganglionic sympathetic fibers from S2-4 but synapse on organ wall distal to splenic flexure