Innervation of Abdominal Viscera: Regulation of G-I Function and Pain Perception Flashcards
For sympathetic innervation with the T5-9 (or 10) spinal cor segment, what is the
- ) Pre-ganglionic splanchnic nerve
- ) Prevertebral ganglion
- ) Greater splanchnic nerve
2. ) Celiac ganglion
For sympthetic innervation with the T10-11 spinal cord segment what is the
- ) Pre-ganglionic splanchnic nerve
- ) Prevertebral ganglion
- ) Lesser Splanchnic nerve
2. ) Superior mesenteric (or aorticorenal) ganglia
For sympathetic innervation with the T12 spinal cord segment, what is the
- ) Pre-ganglionic splanchnic nerve
- ) Prevertebral ganglion
- ) Least Splanchnic nerve
2. ) Aorticorenal (or cell bodies in renal plexus) ganglia
For sympathetic innervation with the L1-2 spinal cord segment, what is the
- ) Pre-ganglionic splanchnic nerve
- ) Prevertebral ganglion
- ) Lumbar Splanchnic nerve
2. ) Inferior mesenteric ganglia
What is the destination of the sympathetic innervation from
- ) T5-6
- ) T7-9
- ) T6-10
- ) Abdominal esophagus
- ) Liver and biliary tree
- ) Stomach, spleen, pancreas, and proximal duodenum
What is the destination of the sympathetic innervation from
- ) T9-T10
- ) T10
- ) T10-T11
- ) Distal duodenum, pancreas, jejunum, and ileum
- ) Appendix
- ) Proximal colon
What is the destination of the sympathetic innervation from
- ) T12
- ) L1-2
- ) Proximal colon
2. ) Distal colon
Pain and pressure afferents follow
-sensitive to distension
Sympathetic pathways
What is the function of sympathetic G-I innervation?
Decreases motility and secretion
Site of synapse in intestinal wall for foregut and midgut
Myenteric and submucous plexuses
Site of synapse in intestinal wall for hindgut
Enteric plexuses
What is the function of parasympathetic G-I innervation?
Increases motility and secretion
What are the two preganglionic nerves of parasympathetic G-I innervation?
- ) Vagus nerve trunks
2. ) S2-4 ventral rami
For the vagus nerve trunks, what is the autonomic plexus?
Celiac plexus and superior mesenteric plexus
For the S2-4 ventral rami, what is the autonomic plexus?
Inferior hypogastric plexus
What is the destination of innervation from the vagus nerve trunks?
Esophagus through proximal 2/3 of transverse colon
Synapse within alimentary tract from esophagus through proximal 2/3 of transverse colon
Intrinsic (enteric) Ganglia
What is the destination of innervation from the S2-4 ventral rami?
Distal 1/3 of transverse colon to rectum
Synapse within alimentary tract from distal 1/3 of transverse colon to rectum
Intrinsic (enteric) Ganglia
Reflex afferents follow
Parasympathetic pathways
The system of neurons and their supporting cells that is found within the walls of the alimentary tract
Enteric Nervous System
Neurons are within ganglia in
Intrinsic plexuses
The main plexuses which contain neurons in ganglia are the
Myenteric (Auerbach’s) and Submucosal (Meissner’s)
The myenteric (Auerbach’s) plexus is between the
Longituginal and circular muscles
The submucosal (Meissner’s) plexus is between the
Circular muscle and muscularis mucosae
Synapse with cells in the same or other ganglia
Intrinsic neurons
Intrinsic neurons project to effectors in the walls of the
Alimentary tract (e.g. muscle, mucosae)
Outside the walls of the alimentary tract, intrinsic neurons connect with
Autonomic ganglia
Intrinsic neurons send afferents to the
CNS
Intrinsic neurons innervate
Mesenteric arteries and arterioles of the colon
Governs the normal motility and secretory functions of the intestine
Enteric nervous system
The enteric nervous systems actions are affected and modified by the
Extrinsic nerve supply
Retains many functions after all central connections are severed
Enteric nervous system
Sympathetic and parasympathetic denervation have a transient effect on
Gut motility
Intrinsic plexuses contain complete reflex pathways consisting of
Enteric neurons, interneurons, and motor neurons
Monitor intestinal wall tension and intestinal contents
Enteric neurons
Form information links between enteric neurons
Interneurons
Change the activity of the intestine
Motor neurons
Involves transfer of impulses from intrinsic sensory neurons via the interneurons to cephalad directed excitatory motor neurons and caudally directed inhibitory motor neuron
Peristaltic reflex
An unpleasant sensation associated with actual or potential tissue damage, and mediated by specific nerve fibers to the brain where its conscious appreciation may be modified by various factors
Pain (symptom/subjective)
Sensitive or painful as a result of pressure or contact that is not sufficient to cause discomfort in normal tissues
Tenderness (sign/objective)
Dull and poorly localized pain resulting from noxious stimulus to abdominal viscus
Abdominal pain
Perceived in the midline because sensory afferents come from both sides of spinal cord
Abdominal pain
What type of abdominal pain is seen in the
- ) Foregut
- ) Midgut
- ) Hindgut
- ) Epigastric
- ) Unbilical
- ) Suprapubic
Corresponds roughly to dermatomes which are innervated by the same spinal cord level from which
diseased organ receives its innervation
Site of abdominal pain
Nerve impulses pass through the pre-vertebral splanchnic ganglia, reach the sympathetic chain in the splanchnic nerves, and enter the dorsal root via the
White ramus communicans
Perceived as originating in areas supplied by the somatic nerves entering the spinal cord at the same segment as the sensory nerves from the organ producing the pain because of shared central pathways by afferent neurons from different sites
Referred pain
usually fairly well localized
Referred pain
Referred pain usually appears when the noxious visceral stimulus becomes
More intense
Results from noxious stimulus to the parietal peritoneum
-Aggrevated by movement or coughing
Parietal pain
What is more intense, parietal pain or visceral pain?
Parietal
In parietal pain, nerve impulses travel within
Somatic sensory nerves
In parietal pain, nerve impulses travel within somatic sensory nerves and the fibers reach the spinal cord in the peripheral nerves corresponding to the
Cutaneous dermatomes from T6 to L1-3
What is the following innervation for the biliary tree and gullbladder?
- ) Parasympathetic via
- ) Sympthetic and visceral sensory via
- ) Somatic afferent fibers via
- ) Vagus nerves
- ) Greater splanchnic nerves
- ) Phrenic nerve
The physiological sphincter at the esophogastric junction is controlled by
Vagal innervation
What is the parasympathetic innervation of the stomach?
anterior and posterior vagal trunks –> celiac plexus –> intrinsice (enteric) ganglia
What does parasympathetic innervation to the stomach do?
Increases motility and acid secretion
What is the sympathetic innervation of the stomach?
T6-9 –> Greater splanchnic –> celiac ganglia –> celiac plexus
What is the parasympathetic and reflex afferent innervation to the appendix?
Vagus nerve
What is the sympathetic and visceral sensory innervation of the appendix?
T10 spinal cord segment
Responsible for regulating peristalsis
Myenteric (Auerbach’s) Plexus
For the parasympathetic system, what is the preganglionic cell body location?
Brainstem (vagus) and S2-S4 (pelvic splanchnic)
For the parasympathetic system, what is the postganglionic cell body location?
Terminal ganglia
For the sympathetic system, what is the preganglionic cell body location?
Lateral horn of T5-L2
For the sympathetic system, what is the postganglionic cell body location?
Prevertebral ganglia
Caused by mutation of the RET gene which causes failure of neural crest cell migration to enteric plexuses
Aganglionic megacolon (Hirschsprung’s Disease)
In Hirschsprung’s the aganglionic (Myenteric Plexus) bowel segment becomes constricted and the proximal segment becomes
Dilated
What is the path of sympathetic innervation to the G-I system starting from the lateral horn of T5-L2?
Lateral horn, through the ventral root, into the ventral ramus, through the white rami communicans into the paravertebral canal, and through the splanchnic nerve into the prevertebral ganglion (synapse) and onto the organ
What is the embryonic region for
- ) T5-T9
- ) T10-T11
- ) T12
- ) L1-L2
- ) Foregut
- ) Midgut
- ) Midgut
- ) Hindgut
In the foregut sympathetic innervation, preganglionic fibers in the greater splanchnic nerves synapse on postganglionic neurons in the
Celiac ganglia
In the midgut sympathetic innervation, preganglionic fibers in the lesser thoracic splanchnic nerves sinapse on postganglionic neurons in the
Superior mesenteric ganglia
In the hindgut sympathetic innervation, preganglionic fibers in the lumbar splanchnic nerves synapse on postganglionic fibers in the
Inferior mesenteric ganglia
The post ganglionic fibers are then distributed to the organ wall/enteric plexus on the branches of the
Inferior mesenteric artery
What is the embryonic region for the parasympathetic nerves with cell bodies located in
- ) Brainstem
- ) S2-S4
- ) Foregut and midgut
2. ) Hindgut
In the foregut parasympathetic innervation, preganglionic fibers in anterior and posterior vagal trunks synapse on postganglionic neurons in
Enteric ganglia
In the midgut parasympathetic innervation, preganglionic fibers in vagal trunks pass through superior mesenteric ganglia and synapse on cell bodies in the
Enteric plexus
In the hindgut parasympathetic innervation, preganglionic fibers in pelvic splanchnic nerves (S2-S4) are distributed on
-synapse on cell bodies in enteric plexus
Arteries within mesentery of rectum and colon
In the foregut, postganglionic sympathetic and parasympathetic fibers are distributed by traveling on the
Celiac trunk
In the midgut, sympathetic (postganglionic) and parasympathetic (preganglionic) fibers are distributed by traveling on the
Superior mesenteric artery