Abdominal Autonomic Innervation

Question 1

Foregut, midgut, and hindgut major blood supply

Answer 1

. Fore: celiac trunk
. Mid: sup., mesenteric a.
. Hind: inf. Mesenteric a.

Question 2

Foregut organs

Answer 2

. Liver 
. Gallbladder
. Cancreas
,. Spleen
. Stomach
. Prox. Half duodenum

Question 3

Midgut organs

Answer 3

. Distal half duodenum through 2/3 transverse colon

Question 4

Hindgut organs

Answer 4

. Distal 1/3 colon through rectum

Question 5

Paravertebral ganglia

Answer 5

. Assoc. w/ structures in body wall

. Sympathetic chain

Question 6

Prevertebral ganglia

Answer 6

. Assoc. w/ structures in body cavity

. Located ant. To vertebral bodies or abdominal aorta

Question 7

General Structures w/in body wall that get sympathetic innervation

Answer 7

. Vessels
. Glands
. Heart and lungs (considered part of body wall)

Question 8

General Structures w/in body cavity that get sympathetic innervation

Answer 8

. Smooth muscles in gut walls, sphincters, arteries, and glands

Question 9

General location of cell bodies of preganglionic ganglia

Answer 9

. T1-L2/3 levels (thoracolumbar outflow)

Question 10

General location of postganglionic sympathetic fibers going to tissue in body wall

Answer 10

. Paravertebral ganglia

Question 11

General location of postganglionic sympathetic fibers going to tissues in body cavity

Answer 11

Prevertebral ganglia

Question 12

Pathway of sympathetic neurons going to tissues in body cavity

Answer 12

. Preganglionic sympathetic neurons travel through white rami communicantes to sympathetic chain but don’t synapse and leave via thoracic/lumbar splanchnic nn.
. Nerves leave thorax and move into abdomen where they synapse in prevertebral ganglia
. Postganglionic sympathetic fibers course in autonomic plexuses on aa. To reach target viscera

Question 13

Autonomic plexuses on aorta

Answer 13

. Mixed
. Contains preganglionic and postganglionic sympathetic fibers going to and from prevertebral ganglia
. Preganglionic parasympathetic fibers going to abdominal viscera
. Visceral sensory fibers coming from abdominal viscera

Question 14

Sympathetic innervation of foregut

Answer 14

. Cell bodies of preganglionic sympathetic neurons at T5-9
. Travel through white rami to sympathetic chain but DONT synapse
. Pass through sympathetic chain and leave in greater thoracic splanchnic n.
. Descends along anterolat. Sides of thoracic/lumbar vertebral bodies
. Greater splanchnic n. Pierces diaphragm and enters abdomen and course on abdominal aorta in autonomic plexuses
. Synapse in celiac ganglion then course w/in autonomic plexuses on branches of celiac trunk to organs

Question 15

General pathway of Sympathetic innervation to small and large intestine

Answer 15

. Cell bodies in T10-L2/3
. Go to sympathetic trunk via white rami and don’t synapse
. Conveyed in thoracic lesser and least and lumbar splanchnic nn.
. Preganglionic fibers travel in autonomic plexuses on aorta to reach sup. And inf. Mesenteric ganglia to synapse
. Postganglionic fibers course in autonomic plexuses on branches of sup. And inf. Mesenteric aa. To organs

Question 16

Sympathetic innervation of midgut only

Answer 16

. T10/11 go through white rami then leave w/o synpasing in lesser thoracic splanchnic n.
. Pierces diaphragm and enters abdomen
. Contribute to autonomic plexuses on aorta and course w/in autonomic plexuses to reach sup. Mesenteric ganglion (SMG) to synapse
. Postganglionic fibers leave SMG and course w/in autonomic plexuses on branches of sup. Mesenteric a. To organs

Question 17

Sympathetic innervation of hindgut only

Answer 17

. T12 and L1-2/3
. Go to trunk via white rami, don’t synapse, leave in least thoracic (T12) and lumbar splanchnic (L1-3) nn.
. Course w/in autonomic plexuses on aorta to inf. Mesenteric ganglion to synapse
. Postganglionic fibers then course w/in autonomic plexuses on branches of inf. Mesenteric a. To organs

Question 18

General parasympathetic pathway to abdominal viscera

Answer 18

. Preganglionic fibers from vagus Cranial n. 10)or pelvic splanchnic nn. (S2-4) called craniosacral outflow
. Vagus n. Provides preganglionic fibers to most of GI tract up to L colic flexure
. Pelvic splanchnic nn. Provide preganglionic fibers distal to L colic flexure
. Preganglionic fibers synapse in enteric ganglia w/in walls of each organ
. Postganglionic fibers course w/in walls of organ

Question 19

general Parasympathetic pathway in abdomen up to L colic flexure

Answer 19

. Preganglionic neurons in R/L vagus nn. W/ cell bodies in brain
. Vagi form ant. And post. Trunks on esophagus
. Enter abdomen as plexuses on esophagus
. Convert preganglionic fibers to abdominal aortic autonomic plexuses that course along branches of aorta to target tissues
. Synapse in organ w/ cell bodies of terminal intrinsic/enteric) ganglia
. Short postganglionic in organ wall

Question 20

General parasympathetic pathway for most of hindgut (distal to L colic flexure)

Answer 20

. Cell bodies in S2-4
. Leave ventral rami of S2-4 coursing w/in pelvic splanchnic nn.
. Pelvic splanchnic nn. Convey preganglionic fibers that synapse in enteric ganglia w/in walls of hindgut
. Short postganglionic fibers course w/in walls of organs

Question 21

Visceral afferents

Answer 21

. Convey pain
. Course along sympathetic fibers but impulse goes in opposite direction
. Enters spinal cord at same level that sympathetic fibers exit spinal cord
. Cell bodies in DRG
. Pain referred to dermatomes assoc. w/ spinal cord level where afferent fibers communicate w/ spinal cord (levels assoc. w/ sympathetic fibers supplying viscera)