Lecture 34: Visceral Nervous System of Abdomen

Question 1

sympathetic: 3 pathways/destinations

Answer 1

-to body wall
-body wall cranial to diaphragm
-body wall caudal to diaphragm

Question 2

parasympathetic: 3 pathways/destination

Answer 2

-head and neck
-body caudal to neck (thorax, foregut, midgut)
-hindgut and pelvis

Question 3

what nerve is preganglionic

Answer 3

vagus

Question 4

what pathways does pain follow

Answer 4

sympathetic
structure –> spinal nerve –> dorsal root ganglion

Question 5

what pathway does non pain follow

Answer 5

parasympathetic to brain

Question 6

where does vagus end

Answer 6

end of midgut

Question 7

foregut: structures (6)

Answer 7

-esophagus
-stomach
-proximal duodenum and pancreas
-liver
-gallbladder

Question 8

midgut structures (6)

Answer 8

-distal duodenum and pancreas
-jejunum
-ileum
-cecum
-ascending colon
-proximal 2/3 transverse colon

Question 9

hindgut: structures (5)

Answer 9

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

Question 10

role of sympathetics in abdomen

Answer 10

restrict blood flow/vasoconstriction to inhibit action of organ = slow down digestion

Question 11

what 2 ways can smooth muscle contraction be inhibited

Answer 11

-sympathetic nerve fibers directly
-enteric nervous system

Question 12

origination of preganglionic sympathetics in abdomen

Answer 12

T5-L4

Question 13

origination of preganglionic sympathetics in abdomen

Answer 13

T1-L4

Question 14

what nerves attach to T5 to coccygeal paravertebral ganglia in abdomen

Answer 14

abdominopelvic splanchnic nerves

Question 15

3 paravertebral ganglia where AP splanchnic nerve can synpase

Answer 15

-celiac
-cranial mesenteric
-caudal mesenteric

Question 16

paravertebral ganglia aka

Answer 16

preaortic ganglia

Question 17

where are celiac, cranial mesenteric and caudal mesenteric ganglia located

Answer 17

abdominal aorta

Question 18

periarterial plexus

Answer 18

synapse occurs at aorta
preganglionics wrap around artery to travel

Question 19

how do sympathetic postganglionic fibers travel after synapsing at celiac/cranial mesenteric/caudal mesenteric

Answer 19

periarterial plexuses to target organ

Question 20

where does hindgut begin

Answer 20

2/3 along transverse colon

Question 21

role of parasympathetics in abdomen

Answer 21

-stimulate abdominal organs
-stimulate contraction of smooth muscle, secretory cells, gland cells

Question 22

preganglionic parasympathetic axons travel to body via (2)

Answer 22

vagus nerve
perarterial plexuses

Question 23

where do parasympathetic axons synapse

Answer 23

wall of target organ

Question 24

parasympathetic preganglionic cell body found in

Answer 24

brain

Question 25

where does lateral horn end

Answer 25

L4

Question 26

what structure does vagal trunks have to travel through to get to abdomen

Answer 26

esophageal hiatus

Question 27

location of perganglionic parasympathetic cell bodies destined for HINDGUT and PELVIC organs

Answer 27

spinal cord anterior horn at S2, S3 and S4

Question 28

what nerves are branches of ventral rami

Answer 28

pelvic splanchnic nerves

Question 29

pathway of preganglionic parasympathetics

Answer 29

lateral/anterior horn –> ventral root –> mixed spinal nerve –> ventral ramus –> pelvic splanchnic nerve

Question 30

what are the sympathetic abdominopelvic nerves

Answer 30

sacral splanchnic nerves

Question 31

pelvic and sacral splanchnic nerves originate from

Answer 31

abdominopelvic splanchnic nerves

Question 32

when do abdominopelvic splanchnic nerves renamed to sacral/pelvic splanchnic nerves (what spinal cord level)

Answer 32

S1

Question 33

pelvic splanchin nerves: sympathetic or parasympathetic?

Answer 33

parasympathetic

Question 34

sacral splanchnic nerves: sympathetic or parasympathetic?

Answer 34

sympathetic

Question 35

visceral pain only occurs from what levels

Answer 35

T1-L4

Question 36

where does referred pain mix up occur

Answer 36

dorsal horn

Question 37

3 cell bodies in dorsal root ganglion of S2, S3 and S4

Answer 37

somatic sensory
pain
nonpain

Question 38

non pain pathway: hindgut

Answer 38

parasympathetic
organ –> plexus –> pelvic splanchnic nerves –> ventral ramus –> mixed spinal nerve –> DSG –> dorsal root –> dorsal horn

Question 39

pain pathway: foregut and midgut

Answer 39

sympathetic
organ –> plexus –> paravertebral ganglion NO synapse –> white ramus communicans –> mixed spinal nerve –> DSG –> dorsal root –> dorsal horn

Question 40

enteric nervous system: definition, location, function

Answer 40

-separate component of ANS for regulating GI tract
-local reflex response with afferent and efferent neurons (plexuses)
-located in wall of GI (esophagus to rectum)

Question 41

2 plexuses in enteric NS

Answer 41

-myenteric/auerbach’s plexus
-submucosal/meissner’s plexus

Question 42

myenteric/auerbach’s plexus: location

Answer 42

between circular and longitudinal layers of smooth muscle in GI tract

Question 43

submucosal/meissner’s plexus: location

Answer 43

submucosa of GI tract

Question 44

parasympathetic: enteric nervous system (function)

Answer 44

stimulate smooth muscle contraction (peristalsis) and glandular secretions

Question 45

sympathetic: enteric NS (function)

Answer 45

-inhibit smooth muscle contraction/peristalsis
-vasoconstriction

Question 46

enteric NS: reflex control of GI

Answer 46

Sensory neurons: perceive distension caused by bolus
At the same time: Stimulate interneurons distal to bolus to relax AND Stimulate interneurons proximal to bolus to contract
Continuous contraction proximal to bolus pushes bolus along

Question 47

hirschprung’s disease: definition, cause, effects

Answer 47

-congenital megacolon
-failure of neural crest migration to form enteric NS
-distal colon can’t generate peristalsis –> fecal matter accumulates in proximal colon –> colon enlarges