Visceral Innervation of the Abdomen Flashcards
what are the 3 distinct pathways of the sympathetic NS
1) to the body wall (ie: hind paws)
2) body cavity cranial to diaphragm
3) body cavity caudal to diaphragm
what are the 3 distinct pathways of the parasympathetic NS
1) head and neck
2) body caudal to the neck: thorax, foregut, midgut
3) hindgut and pelvis
describe pain
damage to visceral structure which follows the sympathetic pathway backward then heads dorsally
describe non pain
sensations such as fullness, bloating and cramping
follows parasympathetic pathway backward
what system is the thoracolumbar system?
sympathetic
what system is the craniosacral system?
parasympathetic
what is the role of the sympathetics in the abdomen?
will inhibit the function of abdominal organs, typically by decreasing blood flow to organs through vasoconstriction
where do thorax sympathetics originate?
T1-T5 –> CP splanchnic nerves attach to C1-T5 paravertebral ganglia
what do abdomen sympathetics originate?
T5-L4 –> AP splanchnic nerves attach to T5 -Coccygeal level paravertebral ganglia
what levels are the body wall found on?
ALL LEVELS
what happens after synapse for postganglionic fibers?
travel in periarterial plexuses along arterial branches to the target organs
what sympathetics supply the celiac trunk?
celiac ganglion
what sympathetics supply the cranial mesenteric artery?
cranial mesenteric ganglion
what sympathetics supply the caudal mesenteric artery?
caudal mesenteric ganglion
where does hindgut begin?
about 2/3 of the way along the transverse colon
what is the role of parasympathetics in the abdomen?
usually will stimulate the abdominal organs (smooth muscle in the walls of the GI tract) and secretory cells in the epithelium, gland cells in the submucosa, and a few organ-specific cells
describe the parasympathetic pathways in the foregut and hindgut
same pathway that has been learned
where are preganglionic parasympathetic cell bodies destined for hindgut and pelvic organs located?
spinal cord anterior horn at levels S2, S3, S4
the sacral splanchnic nerves (sympathetic AP nerves) are branches of:
branches of the sympathetic chain
the pelvic splanchnic nerves (parasympathetic) are branches of:
branches of ventral rami
where might the mix up occur for referred pain for foregut and midgut?
likely dorsal horn (same as thorax)
how does pain travel in the hindgut?
follows the parasympathetic pathway back to the CNS
where does referred pain from hindgut get mixed up?
still occurs in the dorsal horn
how does nonpain travel for the foregut and midgut?
follows the vagus nerve to the brainstem
how does nonpain travel for the hindgut
follows the pelvic splanchnics
what cell bodies live in the dorsal root ganglion of S2, 3 and 4?
pain, nonpain, somatic sensory
what is the enteric nervous system?
-classified as a separate component of the ANS for regulating the GI tract
-acts as a local reflex response with afferent and efferent neurons acting through an array of excitatory and inhibitory interneurons
where is the myenteric (auerbach’s) plexus located in the GI tract
between circular and longitudinal layers of smooth muscle
where is the submucosal (meissner’s) plexus located in the GI tract
submucosa
what does the parasympathetic do in the enteric nervous system
stimulates smooth muscle contraction directly and through the ENS indirectly
stimulates glandular secretions
what does the sympathetic do in the enteric nervous system?
-inhibits smooth muscle contraction directly and through the ENS indirectly
-vasoconstriction
-isolation of the GI tract from autonomics does not greatly diminish ENS function
how does movement in the GI tract work?
1) sensory neurons perceive the distension by the caused by the bolus
2) stimulate interneurons distal to it to relax, proximal to it to contract
3) continuous contraction proximal to the bolus pushes the bolus along the GI tract
what is hirschprung’s disease (congenital megacolon)
-failure of neural crest to migrate and form teh ENS
-distal colon can not generate peristalsis, fecal matter accumulates in proximal colon and proximal colon enlarges
