Gut book 7: Lymphatics & Autonomics of the Abdomen Flashcards
Abdominal parietal lymphatics
Composed of a chain of lumbar nodes and their lymphatic channels that ascend the aorta thereby forming lumbar trunks.
Afferents to the lumbar trunks
external and internal iliac trunks that bring lymph from the lower limb, pelvis, perineum, gluteal area and lower abdominal wall.
Lumbar nodes receive lymph primarily from
retroperitoneal structures: kidneys, ureters, suprarenal glands, lateral and posterior abdominal wall, and the abdominal surface of the diaphragm, as well as from the testes, ovaries, uterine tubes and superior portion of the uterus.
Note: the left lumbar trunk receives a portion of hte lymphatic drainage fo the inferior mesenteric nodal system as well as the INTESTINAL LYMPHATIC TRUNK 70%^ of the time.
Lumbar trunks join at
approximately LV1-2 and in 25% of the specimens form a dilatation, the cisterna chyli, located posterolaterally to the aorta under the right crus of the diaphragm.
The cysterna chyli is drained by
the thoracic duct, which passes through the aortic hiatus between the right crus and the aorta to end in the left jugulovenous angle.
Abdominal visceral lymphatics are composed of
a chain of mesenteric and celiac nodes and their lymphatic channels that receive lymph from the organs of digestion via specific organ lymph nodes and lymphatic channels.
Lymphatics draining visceral structures parallel the specific arterial supply of those viscera and therefore drain to nodes named for the three ventral unpaired arteries: celiac, superior and inferior mesenteric.
Inferior mesenteric nodes
Nodes located at the root of the inferior mesenteric artery
receive lymph from the rectum, sigmoid colon and descending colon via sigmoid and left colic nodes
major drainage of inferior mesenteric nodes is to superior mesenteric nodes; minor drainage is to the left lumbar trunk.
Superior mesenteric nodes
nodes located at the root of the mesentery
receive lymph from the transverse and ascending colon, ileum and jejunum via mesenteric, ileocolic, right colic and middle colic nodes as well as lymph from the inferior mesenteric nodes.
Major drainage of superior mesenteric nodes is to celiac nodes; minor drainage is to the intestinal trunk.
Celiac nodes
nodes clustered at the root of the celiac trunk
receive lymphatic channels from the liver, stomach, pancreas and spleen via hepatic, gastric and pancreaticosplenic nodes as well as lymph from the superior mesenteric nodes.
Celiac nodes drain to the intestinal lymph trunk.
Hepatic lymphatics
drain superiorly through the caval, esophageal and sternocostal hiatuses.
What receive drainage from the distal portion of the esophagus above the diaphragm.
gastric nodes located near the cardia
Intestinal lymph trunk
formed by efferent lymphatic channels of the celiac nodes joined by the minor drainage of the superior mesenteric nodes
Drains either to the cisterna chyli (30%) or to the left lumbar trunk (70%)
lymphogenous spread of cancer cells from the organs of digestion
will eventually spread to celiac nodes and from there to the cisterna chyli and ultimately through the thoracic duct to the venous system.
Abdominal sympathetic innervation originates… and travels
in thoracic and lumbar segments of the spinal cord and travels to collateral (pre-aortic) ganglia via thoracic and abdominal (lumbar),, splanchnic nerves.
Abdomominal parasympathetic innervation originates… and travels
in the brainstem (dorsal motor nucleus of the vagus) and in spinal cord segments S2,3,4 and travels to submucosal and myenteric ganglia via the vagus and pelvic splanchnic nerves, respectively.
What do abdominal parasympathetic and sympathetic systems contain?
visceral efferent and afferent fibers that form autonomic plexuses on the surface of arterial blood vessels.
Parasympathetic activity in the abdomen stimulates
glandular secretion and peristalsis and causes relaxation of sphincters
sympathetic activity in the abdomen does what?
constricts the sphincters, increases vasomotor tone, and decreases glandular secretion.
Parasympathetic afferents (GVA fibers) register..
hunger, nausea and distension, contribute to visceral reflexes and return to the CNS via the vagus nerve and along pelvic splanchnic nerves to sacral nerves and dorsal root ganglia at S2,3,4
Afferents that travel with the sympathetic system register…
acute pain from viscera and mesenteries and course to the CNS via splanchnic nerves, spinal nerves and dorsal root ganglia at T1-L2(3)
Abdominal sympathetic trunk
the thoracic sympathetic trunk continues into the abdomen by passing beneath the medial arcuate ligament.
lying superficial to the medial border of the psoas, it hugs the lateral surface of the vertebral bodies becoming more ventral as it descends.
Ganglia in the lumbar region are irregular, numbering 2-6
The lumbar sympathetic trunk receives…
white rami communicantes from L1, L2 and sometimes L3, although illustrations you may encounter include L4.
Abdominal aortic autonomic plexus subsidiary plexuses
autonomic fibers cover the anterior and lateral surfaces of the aorta forming an intricate abdominal aortic autonomic plexus divisible into: celiac plexus intermesenteric plexus superior hypogastric plexus inferior hypogastric plexus
Celiac plexus
from the root of the celiac artery to the superior mesenteric artery
intermesenteric plexus
between the aortic origins of the superior and inferior mesenteric arteries
superior hypogastric plexus
from the root of the inferior mesenteric artery to the sacrum below the aortic bifurcation anterior to LV4-SV1
inferior hypogastric plexuses of the pelvis
via the hypogastric nerves. The single superior hypogastri plexus bifurcates forming two hypogastric nerves which descend on either side of the rectum to join the inferior hypogastric plexuses located there.
What do the abdominal autonomic plexuses contain?
preganglionic sympathetic fibers (from splanchnic nn),
postganglionicrs (from ganglia associated with the plexuses)
preganglionic parasympathetic fibers (from the vagus n. and pelvic splanchnic nn) and
sympathetic prevertebral ganglia, i.e. celiac, aorticorenal, superior and inferior mesenteric ganglia, which contain postganglionic sympathetic cell bodies.
how do postganglionic sympathetic and preganglionic parasympathetic fibers travel from the autnomic abdominal plexuses?
to the derivatives of the foregut, midgut and hindgut via subsidiary plexuses located onthe surface of arterial blood vessels, i.e. celiac plexus, left gastric plexus, splenic plexus, hepatic plexus, superior & inferior mesenteric plexuses, renal plexus, and hypogastric plexuses.
Sympathetic splanchnic nerves provided to the abdomen and pelvis
Greater splanchnic n (T5-T9)- to celiac & superior mesenteric ganglia
Lesser splanchnic n (T10-T11)- to aorticorenal & superior mesenteric ganglia
Least splanchnic n (T12)- to renal plexus & inferior mesenteric ganglion
Lumbar splanchnic nn. (L1-L2(3) - to inferior mesenteric ganglion, renal, intermesenteric and hypogastric plexuses.
Sacral splanchnic nn. (L1-L2)- descend in the sympathetic chain to synapse in the pelvic portion of the chain ganglia before joining the inferior hypogastric plexus of the pelvis OR pass directly into the hypogastric plexus to synapse on scattered ganglia cells located there.
Lumbar splanchnic nn. WHICH DO NOT synapse in the inferior mesenteric ganglion, synapse…
on scattered ganglia cells located diffusely within the renal, superior and inferior mesenteric plexuses.
What provide the major supply of sympathetic innervation to pelvic structures?
lumbar splanchnic nerves.
Greater splanchnic n
(T5-T9)-to celiac & superior mesenteric ganglia
Lesser splanchnic n
(T10-T11)- to aorticorenal & superior mesenteric ganglia
Least splanchnic n
(T12)- to renal plexus & inferior mesenteric ganglion
Lumbar splanchnic nn.
(L1-L2(3) - to inferior mesenteric ganglion, renal, intermesenteric and hypogastric plexuses.
Sacral splanchnic nn.
(L1-L2)- descend in the sympathetic chain to synapse in the pelvic portion of the chain ganglia before joining the inferior hypogastric plexus of the pelvis OR pass directly into the hypogastric plexus to synapse on scattered ganglia cells located there.
Anterior and posterior vagal esophageal trunks descend…
on the surface of the stomach providing gastric and hepatic branches, join the celiac ganglion without synapsing and continue to join the abdominal aortic autonomic plexus.
Preganglionic parasympathetic fibers of the vagus nerve distribute…
with the sympathetic elements of the celiac, aorticorenal, and superior mesenteric plexuses along arterial blood vessels to their terminal destinations (components of the gut from the stomach to the distal 2/3 ofo the transverse colon and accessory organs of digestion- liver, gallbladder and pancreas.
Are preganglionic parasympathetic fibers (vagal) found in the intermesenteric plexus?
No; their distribution ends with the distribution of the superior mesenteric plexus.
Distal to the distal 1/3 of the transverse colon the preganglionic fibers originate from …
the parasympathetic I.M.L.C.C. of the sacral spinal cord at levels S 2,3,4
the pelvic splanchnic nerves merge with what?
the inferior hypogastric plexuses of the pelvis
Fibers destined to innervate the distal 1/3 of the transverse colon, descending and sigmoid colon, ascend…
from the pelvis exclusive of the hypogastric nerves, travel parallel to the rectum, sigmoid and descending colon WITHIN the attachments of the SIGMOID MESOCOLON and distribute among the perivascular plexuses found there.
What provide postganglionic parasympathetic innervation to target organs?
Parasympathetic ganglia located in the walls of the organs to be innervated.
Innervation of the thoracic esophagus
accomplished by nerves of the thorax
upper 1/2- vagus & recurrent laryngeal nn. (skeletal muscle innervation)
lower 2/3- esophageal plexus
Sympathetic components of lower 2/3 esophagus innervation
reach the esophagus (esophageal plexus) via various routes:
- derived from branches of the sympathetic trunk directly via the cardiac and pulmonary plexuses (T2-6)
- branches of the GREATER SPLANCHNIC NERVE; cord levels T5-%9
decreases peristalsis and glandular secretion; increases vasomotor tone
Parasympathetic component to the lower 2/3 esophagus innervation
vagal esophageal plexus. increases peristalsis and glandular (mucous) secretion
Supracolic compartment (forgut) innervations
a. preganglionic sympathetic fibers from the greater splanchnic n. synapse on postganglionic cell bodies in the celiac ganglion located at the base of the celiac trunk.
b. The posterior vagal trunk joins the celiac plexus; the anterior vagal trunk provides branches to the hepatic plexus, stomach, duodenum and dorsal pancreas.
c. Postganglionic sympathetic fibers from the celiac ganglion along with preganglionic vagal fibers distribute via the celiac, left gastric, splenic and hepatic plexuses.
Sympathetic innervation of abdominal esophagus, stomach, proximal duodenum and dorsal pancreas- origins and effects
Sympathetic origins: spinal cord levels T6-T9; synapse in celiac ganglion
Overall effects: decrease peristalsis, closes pyloric sphincter, decrease glandular secretion, increase vasomotor tone, afferents for acute pain
Parasympathetic innervation of abdominal esophagus, stomach, proximal duodenum and dorsal pancreas- origins and effects
origin: preganglionic- anterior & posterior vagal trunks; postganglionic cell bodies located in wall of organs
Overall effects: increases peristalsis; relaxes pyloric sphincter. Increases HCl secretion (stomach); increases elaboration of pancreatic enzymes.
NOTE: secretion of pancreatic enzymes is hormonally controlled
Afferents for distension
Liver, gallbladder & extra-hepatic biliary tree, hepatopancreatic ampulla sympathetic origins & effects
origins: spinal cord levels T6-T9
Synapse in celiac ganglion; distribute via the hepatic plexus
Effect: increases vasomotor tone
afferents for acute pain refer to central epigastrium
Liver, gallbladder & extra-hepatic biliary tree, hepatopancreatic ampulla parasympathetic origins & effects
origins: contributions to hepatic plexus via the anterior vagal trunk
a. Effect on the liver ill-defined and uncertain
b. effects (gallbladder): secondary influence on contraction of the gallbladder & extra-hepatic biliary tree smooth muscle and relaxation of the hepatopancreatic sphincter (primary effects are hormonal.)
Liver, gallbladder & extra-hepatic biliary tree, hepatopancreatic ampulla sensory innervation
right phrenic n.
Spleen sympathetic origins & effects
T6-T8; synapse in celiac ganglion; distribute via the splenic plexus.
effects:
- vasomotor and contractile to smooth muscle of capsule
- GVAs (pain) from parenchma ill defined; refers to central epigastrium
referred pain from distended capsule and stretched peritoneal ligamentous attachments is to the posterior left upper quadrant
parasympathetic innervation to the spleen…
is not described
Infracolic compartment I: distal 1/2 of duodenum, ventral pancreas, jejunum, ileum, cecum & appendix, ascending colon, proximal 2/3 of transverse colon (midgut derivatives):
Autonomic components
- Preganglionic sympathetic fibers from spinal cord levels T8-T11 via greater, lesser, synapse on postganglionic cell bodies in the celiac and superior mesenteric ganglia, respectively.
- postganglionic fibers from the celiac and superior mesenteric ganglia along with preganglionic vagal fibers (post. Vagal trunk) distribute to the distal 1/2 of the duodenum, head of the pancreas, jejunum, ileum, cecum, appendix, ascending and proximal 2/3 of the transverse colon, via the superior mesenteric plexus located on the superior mesenteric a. and its branches.
Infracolic compartment I: distal 1/2 of duodenum, ventral pancreas, jejunum, ileum, cecum & appendix, ascending colon, proximal 2/3 of transverse colon (midgut derivatives):
Sympathetic effects
decrease peristalsis
increase vasomotor tone
decrease glandular secretion
afferents for acute pain refer to T8-11; acute pain from the appendix is specfically referred to the area of the umbilicus (T10)
Infracolic compartment I: distal 1/2 of duodenum, ventral pancreas, jejunum, ileum, cecum & appendix, ascending colon, proximal 2/3 of transverse colon (midgut derivatives):
Parasympathetic effects
increase glandular secretion & elaboration of pancreatic enzymes
increase peristalsis
vagal afferents for distension (cramping)
Infracolic compartment II: distal 1/3 of the transverse coon, descending colon & sigmoid colon (hind gut dreivatives):
Autonomic components
- Preganglionic sympathetic fibers from spinal cord levels T12-L2(3) via least and lumbar splanchnic nn. synapse on postganglionic cell bodies in the inferior mesenteric ganglion.
- Preganglionic parasympathetic fibers originating at spinal cord levels S2,3,4 (pelvic splanchnic nn.) ascend from the pelvis within the sigmoid mesentery.
- Postganglionic fibers from the inferior mesenteric ganglion along with pelvic splanchnic nn. distribute to the distal 1/3 of the transverse colon, descending colon & sigmoid colon via the inferior mesenteric plexus located on the inferior mesenteric a. and its branches
Infracolic compartment I: distal 1/2 of duodenum, ventral pancreas, jejunum, ileum, cecum & appendix, ascending colon, proximal 2/3 of transverse colon (midgut derivatives):
sympathetic effects
decrease peristalsis
increase vasomotor tone
decrease glandular secretion
afferents for acute pain refer to T12-L2-3
Infracolic compartment I: distal 1/2 of duodenum, ventral pancreas, jejunum, ileum, cecum & appendix, ascending colon, proximal 2/3 of transverse colon (midgut derivatives):
parasympathetic effects
increase peristalsis
increase glandular secretion
afferents for distension (cramping)
Infracolic compartment III: rectum, anal canal proximal to pectinate line (hindgut derivatives):
autonomic componnts
a. preganglionic sympathetic fibers from spinal cord levels L1-2(3) provide lumbar splanchnic nn. which synapse in the inferior mesenteric ganglion OR within diffuse sympathetic ganglia cells located in the intermesenteric/ superior hypogastric plexus. These postganglionic sympathetic fibers descend into the pelvis within the hypogastric n. to enter teh inferior hypogastric and rectal plexuses.
b. Sacral splanchnic nn. (L1-2) descend within the sympathetic chain and exit within the pelvis to join the inferior hypogastric plexus where thye will synapse in scattered ganglial cells located there.
c. Pelvic splanchnic nn. enter the inferior hypogastric plexus directly.
Infracolic compartment III: rectum, anal canal proximal to pectinate line (hindgut derivatives):
Sympathetic effects
decrease peristalsis
increase vasomotor tone
decrease glandular secretion
Infracolic compartment III: rectum, anal canal proximal to pectinate line (hindgut derivatives):
Parasympathetic effects
increase peristalsis
increase glandular secretion
afferents for distension
Afferents for acute pain and distension from the distal sigmoid and anal canal above the pectinate line return to…
spinal cord levels S 2,3,4
Anal Canal Distal to pecinate line innervation
a. somatic innervation only
b. Accomplished by branches of inferior rectal n.
1. Branch of the pudendal n. (S 2,3,4)
Hirschsprungs Disease (Aganglionic/ Toxic Megacolon)
Due to failure of neural crest cells to colonize a portion of the gut, usually distal colon and rectum, resulting in lack of development of submucosal and intramural autonomic ganglia.
Results in a constricted segment of the colon (acting as a sphincter due to chronic tonic contraction of visceral smooth muscle) which will not relax causing the fecal mass to build up proximal to the obstruction.
Mapping of cutaneus portion of the body
The sensory portion of the brain is accurately “mapped” for the cutaneous portion of the body. We can accurately sense the movement of any hair on our body. A fly lands on our skin anywhere we are cognizant thereof. The reason for this is that external effectors can cause us long-term damage if we are not immediately aware of their presence, i.e. fire, sunberno, venemous spders, broken glass, etc.
Body cavity innervation precision
The linings of the body’s cavities are not as precisely innervated as is the outside of the body. We do not need to know that the cheeseburger we ate hours ago is passing form the stomach to the duodenum, or rounding a particular bend in the ileum. Sensations received from our viscera are largely reduced to distension and pain.
Segmental innervation of viscera
Viscera are segmentally innervated by branches of spinal nerves that correlate to the dematomes. RECALL: Afferent fibers for pain travel with the sympathetic visceral motor system. Therefore, dermatomes which are implicated in referred pain syndromes are limited to levels T1-L2(3)
Afferent (sensory) tract neurons (fibers which ascend from the spinal cord to the brain) conduct…
both cutaneous and visceral sensation centralward, usually at different times (due to the difference in mapping for specific dermatomes vs. nospecific body cavity innervation)
Normally, stimulation of visceral afferent fibers is…
sub-threshold, viz. their stimulation is not perceived.
When disease or infection occur internally over a long period of time, visceral afferents may fire more often, thereby stimulating…
ascending tract neurons to the point that their stimulation is perceived. Because these tract neurons are being fired more often, the brain incorrectly interprets the pain as coming from the SURFACE of the body at the same spinal level as the incoming visceral afferents. This is the basis of referred pain: internal pain is said to be ‘referred’ to a specfic area of the outside of the body.
