Lecture 26: Visceral Innervation of the Abdomen

Question 1

three distinct pathways of the SYMPATHETIC NS

Answer 1

1. to the body wall
2. to the body cavity cranial to the diaphragm
3. to the body cavity caudal to the diaphragm

Question 2

three distinct pathways of the PARASYMPATHETIC NS

Answer 2

1. head and neck
2. body caudal to neck (thorax, foregut, midgut)
3. hindgut and pelvid

Question 3

visceral pain

Answer 3

damage to visceral structure which follows the sympathetic pathway from the structure to the spinal nerve and then to the DRG

Question 4

visceral non pain

Answer 4

sensations like fullness, bloating, cramping
follows the parasympathetic pathway to the brain

Question 5

What structures are included in the foregut

Answer 5

• distal esophagus
• stomach
• proximal duodenum + pancreas
• liver
• gallbladder

Question 6

What structures are included in the midgut

Answer 6

• distal duodenum + pancreas
• jejunum, ileum, cecum
• appendix
• ascending colon
• proximal 2/3rds of transverse colon

Question 7

What structures are included in the hindgut

Answer 7

• distal 1/3 of transverse colon
• descending colon
• sigmoid colon
• rectum
• proximal anal canal

Question 8

What is the general role of sympathetics in the addomen?

Answer 8

sympathetics usually inhibit the function of abdominal organs by decreasing blood flow to them via vasoconstriction

Question 9

what ways can sympathetic nerve fibers inhibit the contraction of SM in GI tract

Answer 9

• directly
• indirectly through the enteric NS

Question 10

all preganglionic sympathetic originate in the lateral horn of ____- _____

Answer 10

T1-L4

Question 11

For the thorax, preganglionic sympathetics originate in ____-_____

Answer 11

T1-L5

Question 12

CP splanchnic nerves attach to ___ - ____ paravertebral ganglia

Answer 12

C1-T5

Question 13

For the abdomen, preganglionic sympathetics originate in ____-____ and AP splanchnic nerves attach to ____ - _____

Answer 13

T5-L4 and AP splanchnic from T5-Co (end)

Question 14

are abdomen preganglionic sympathetics myelinated?

Answer 14

yes b/c preganglionic

Question 15

AFTER SYNAPSE, postganglionic fibers travel in the ________ along arterial branches to the target organs

Answer 15

periarterial plexus

Question 16

what part of the GI tract is the transition bw the foregut and midgut

Answer 16

duodenum

Question 17

where does the hindgut begin

Answer 17

about 2/3 of the way along the transverse colon

Question 18

what things will parasympathetics stimulate in the abdominal organ

Answer 18

mostly smooth muscle in the walls of the GI tract
also secretory cells in the epithelium
gland cells in the submucosa
a few organ-specific cells (like chief cells of the stomach)

Question 19

what is the location of preganglionic parasympathetic cell body

Answer 19

brain

Question 20

the preganglionic parasympathetic axons travels to the body via the ____

Answer 20

vagus nerve (CN X)

Question 21

where do preganglionic axons synapse

Answer 21

in small ganglia in the wall of the organ to be innervated

Question 22

preganglionic parasympathetic cell bodies destined for the hindgut and pelvic organs are located in the spinal cord ventral horn at what levels

Answer 22

S2,3,4 (Craniosacral)

Question 23

preganglionic parasympathetics pass through the _____and the _____ to enter the ventral ramus

Answer 23

ventral root and spinal nerve

Question 24

Hindgut pain follows what pathway back to the CNS

Answer 24

parasympathetic

Question 25

referred pain from hindgut…where does mix up occur

Answer 25

dorsal horn

Question 26

For the foregut and midgut, non-pain follows what nerve to the brainstem

Answer 26

vagus

Question 27

for the hindgut, non-pain follows what nerve

Answer 27

pelvic splanchnics

Question 28

what cell bodies live in the dorsal root ganglion of S2,S3,S4

Answer 28

pain, nonpain, somatic sensory

Question 29

role of parasympathetics in the enteric NS

Answer 29

stimulate smooth muscle contraction directly and through the ENS directly

stimulates glandular secretions

Question 30

role of sympathetics in the ENS

Answer 30

inhibit smooth muscle contraction directly and indirectly through ENS
- vasoconstriction

Question 31

What is Hirschprung’s diease (congenital megacolon)

Answer 31

failure of the neural crest to migrate and form the ENS
- distal colon cannot generate peristalsis, fecal matter accumulates in the proximal colon, causing it to enlarge