ABDOMINAL INNERVATION Flashcards
(29 cards)
The nerves for sympathetic innervation of the GI are located in spinal levels ____ to ____. The ___ level innervates the head, the ____ levels for the thorax and the ____ levels for the lumbar GI.
T5-L2 spinal nerves provide SNS innervation to GI. T1 supplies the head, T2-T4 goes to the thorax and T5-T9 supplies the lumbar GI.
The autonomic nervous system innervates the GI both parasympathetically and sympathetically. If the PSNS acts, that serves to increase ________ and ______. The SNS acts to _______ and _______.
PSNS - increase motility and secretion;
SNS - vasoconstrict GI vessels and reduce motility.
The pre-ganglionic cell body locations of the PSNS for the gut are located in the _______ and _______. The PSNS post-ganglionics synapse on the __________.
Brain stem via the Vagus nerve or Sacral spinal cord (S2-4) via the Pelvic Splanchnics nerve;
Terminal ganglia directly on the Organ wall
The pre-ganglionic cell bodies for the SNS of the gut lie in the ______ ____ of the spinal cord through the spinal nerves ____ to ___. The post-ganglionics of the gut SNS are located in the _______ _____ near the spinal cord.
Lateral horn, T5-L2;
Prevertebral “pre-aortic” ganglia
Describe the location and roles of the myenteric plexus, within the enteric nervous system.
Myenteric Plexus is located between smooth muscle walls of the enteric nervous system. Through PSNS innervation, it modulates the gut wall, increases motility and peristalsis. If innervated by SNS, it increases muscular and vascular tone.
Describe the location and roles of the submucosal plexus, in the enteric nervous system.
Submucosal plexus is located in the submucosal layer, DEEPER to the circular layer of smooth muscle. Through SNS innervation, it modulates fluid transport; but through PSNS it acts as a secretomotor.
The SNS fibers in the enteric nervous system are already ____-_______. Yet the PSNS fibers in the enteric nervous system synapses on ________.
Post-ganglionic fibers;
Wall of the gut.
Define peristalsis in the intestinal tract.
Plexuses in the enteric SM wall stimulate relaxations and contractions. The outer longitudinal layer contracts in FRONT of the bolus, whereas the inner circular layer contracts BEHIND the bolus.
Describe the cause of Hirschsprung’s Disease.
Aganglionic Megacolon is caused by a defect in neural crest cell migration from the mutated RET proto-oncogene. This leads to the constriction of the aganglionic distal segment and a dilated proximal segment.
Describe the pathophysiology and treatment of Hirschsprung’s Disease.
Absent enteric ganglions cause an overriding SNS and PSNS innervation. The SNS dominates smooth muscle tone that causes constriction at the aganglionic segment. This causes UNCOORDINATED peristalsis at the proximal end with ganglions. The Pull-through operation takes out the aganglionic segment and leaves the proximal end.
What is the function of splanchnic nerves?
Splanchnic nerves are preganglionic fibers that connect the sympathetic chain to pre-vertebral ganglion. They innervate abdominal viscera.
Pre-vertebral sympathetics have the same name as ________. If sympathetics come from a certain spinal cord level, then the afferents will ____ ______ to the same level.
Arteries;
Go back
What splanchnic nerve supplies sympathetic innervation to the the foregut and where are its pre-ganglionic cell bodies? Where are its pre-vertebral ganglia located?
Greater Thoracic spinal nerves, (T5-T9 level);
Synapse on Celiac ganglia
What splanchnic nerve supplies sympathetic innervation to the the midgut and where are its pre-ganglionic cell bodies? Where are its pre-aortic ganglia located?
Lesser and Least Throracic Nerves, (T10-T12);
Superior mesenteric ganglia (for proximal midgut),
Aortico-renal ganglia (for distal midgut)
What splanchnic nerve supplies sympathetic innervation to the the hindgut and where are its pre-ganglionic cell bodies? Where are its pre-aortic ganglia located?
Lumbar Spinal nerves, (L1-L2);
Inferior Mesenteric ganglia
PSNS pre-ganglionic fibers coming from the brain stem travel through _____ nerves and synapse on the organ walls of the _____ and ______.
Vagus nerve/Vagal trunks;
Foregut and midgut
PSNS pre-ganglionic fibers coming from the sacral region (S2-S4) travel through the _____ _____ nerves to synapse on the enteric plexus of the ______.
Pelvic Splanchnic nerves;
Hindgut
The Posterior vagal trunk travels through the ____ plexus to provide PSNS innervation to the _____. It’s preganglionic fibers run along the branches of the celiac ______ to synapse on the organ wall.
Celiac plexus,
Foregut;
Celiac arteries
Pre-ganglionic vagal trunks pass through the _____ ____ ganglia where it’s fibers travel along the SMA branches. These provide PSNS innervation to the organs of the _____.
Superior mesenteric ganglia;
Midgut
The hindgut is innervated by pre-ganglionics of the ____ ____ nerves. These nerves are distributed on arteries within the ________ of the rectum and colon and synapse on the cell bodies of the ____ ____.
Pelvic Splanchnic nerves;
Mesentery of the rectum and colon;
Enteric plexus
Referred pain of the visceral abdominal organs travels exclusively through fibers of the __________ pathway.
Sympathetic pathway
Trace the afferents nerve pathway of a distended stomach after a large meal. Be specific in labeling the nerves.
Distended stomach > Afferent fiber > Celiac Ganglion > Greater Thoracic Splanchnic Nerve > Para-vertebral ganglion (T5-T9, foregut) > White Ramus Communicans > Ventral ramus > DRG > Dorsal Root > Dorsal Horn > CNS
Trace the nerve pathway for a distended duodenum.
Distended foregut duodenum > info transmitted to proper level in spinal cord (T5-T9) > level responds back with REFLEX.
This is not perceived as pain!
This type of abdominal pain is poorly localized, dull and occurs at the ________. It occurs in very general regions.
Visceral pain;
Midline
