lecture 4 visceral pain Flashcards
what does the enteric nervous system consist of
400-600 million intrinsic neurones that extend most of length of GIT
what is the ENS arranged in
glanglionated plexuses with interconnecting bundles of unmyelinated nerve fibres
what is the function of the ENS
enable GIT to preform basic reflex functions of secretion, absorption, mixing and gut movement without influence of CNS or ANS
how does the CNS communicate with ENS intrinsic neurones to modulate GIT functions
via sympathetic and parasympathetic nerves
where do axons of intrinsic neurones of ENS also project to
sympathetic ganglia, pancreas, gall bladder, trachea, spinal cord, brain stem
structure of GIT (lumen to exterior)
lumen - mucosa (lamina propria and muscularis mucosae; glands) - MALT - submucosa (glands; submucosal plexus of Meissner) - muscularis (for peristalsis; circular then myenteric plexus of Auerbach, then longitudinal) - serosa (epithelium) - mesentery (nerve and artery)
where is intrinsic network of neurones of ENS situated
2 plexuses in tissues of gut wall from oesophagus to anus (submucosal and muscularis)
structure and divisions of ANS
different to somatic NS (ganglia, myelination, neurotransmitters); 2 divisions (sympathetic and parasympathetic) which innervate organs of abdomen and pelvis
where does ANS arise from
different anatomical regions of CNS; sympathetic from spinal cord segments T1-L2, parasympathetic from cranial nerves III, VII, IX, X in brain stem, and spinal cord segments S2-S4
slide 8
sympathetic chain; ganglia form separate spinal cord segments; parasympathetic: vagus to abdomen, sacral parasympathetic outflow to pelvis
functions of efferent ANS nerves to abdomen
motor to smooth muscle; secretomotor to glands
functions of afferent ANS nerves to abdomen
sympathetic: pain; parasympathetic: specific functional sensation e.g. stretch
sympathetic nerves to abdomen (visceral)
from T1-L2; sympathetic trunks, diaphragm, splanchnic (visceral) nerves, coeliac ganglion
vagus nerves to abdomen (visceral)
left and right vagus nerves splitting into anterior and posterior vagul trunks
sympathetic chain to abdomen: greater splanchnic nerve level
T5-T9
sympathetic chain to abdomen: lesser splanchnic nerve level
T10-T11
sympathetic chain to abdomen: least splanchnic nerve level
T12
nerves from lumbar sympathetic chain
go to different parts; all splanchnic nerves and autonomic plexus won’t be retained in dissection
parasympathetic supply
vagus (cranial nerve X) and S2-S4
what ANS division goes to peripheral vessels and skin
sympathetic
what do sympathetic nerves run with to same region of peripheral vessels and skin
somatic nerves (no parasympathetic supply to somatic nerves; don’t run with spinal nerves)
what do autonomic nerves run with to same organs which lack somatic innervation
arteries, but a few run separately
peripheral distribution of ascending sympathetics
C1/C2-C8 (posterior and anterior ramus)
peripheral distribution of descending sympathetics
L3-coccyx (posterior and anterior primary rami)
T1 to L2
lateral horn of spinal cord to sympathetic chain to body wall
sympathetic nerves to viscera
greater, lesser and least splanchnic nerves, lumbar splanchnic nerves (L1-L2), sacral splanchnic nerves from paravertebral sympathetic trunk
where are ANS nerves to abdomen routed via and where is this
preverterbal plexus at midline of body surrounding abdominal aorta and its branches, synapse at ganglia associated with plexuses
what are plexuses and ganglia named according to
associated blood vessels
autonomic plexuses and ganglia
anterior (left) vagal trunk, superior mesenteric ganglion, inferior mesenteric ganglion, sympathetic trunk and ganglion, coeliac trunk and ganglion, renal plexus and ganglion, superior hypogastric plexus (at bifurcation of abdominal aorta), inferior hypogastric plexus
what are the 3 nerve plexuses and ganglia around aorta and branches
parasympathetic nerves from vagus, sympathetic nerves from sympathetic chain T5-L2, parasympathetic nerves from S2-S4
organs supplied by nerve plexuses and ganglia around aorta and branches; sympathetic ganglion chain continue to coccyx to form plexus
coeliac artery (T5-9, vagus), superior mesenteric artery (T10-11, vagus), renal arteries (T10-12, vagus), testicular/ovarian arteries (T10-11, vagus), inferior mesenteric artery (T12-L2, S2-4), superior and inferior hypogastric plexuses (T12-L2, S2-4)
what is referred pain
pain referred from visceral organs and diaphragm (contains somatic nerves but no “sensory map”) to dermatomes supplied by nerves with same segmental supply (autonomic nerve supply in abdomen)
define dermatome
area of skin supplied by single spinal nerve
significance of overlapping dermatomes
at least 3 spinal nerves would have to be blocked to produce region of complete anaesthesia
what cervical level is there no dermatome
C1
dermatomes in limbs
larger (more drawn out)
sensory map of cerebral cortex
lips, hand and face more sensitive
motor map of cerebral cortex
hand and face more innovated
abdominal regions
9 abdominal regions so referred pain to these
what level is the epigastric region
T7/T8 (sympathetic and somatic)
visceral source of epigastric pain
referred pain from foregut structures, as far as duodenal papilla
structures involved in epigastric referred pain
stomach, proximal duodenum, pancreas, liver, gall bladder
visceral source of umbilical pain
T10; referred pain from midgut structures, from duodenal papilla to splenic flexure
what can be referred to periumbilical region
inflamed appendix pain
feature of periumbilical region
colicky (intermittent with bowel contractions)
where do afferent pain fibres from midgut structures enter spinal cord
T10 (same as umbilical dermatome region)
what level is inguinal region
T12/L1
progression of pain in appendicitis (type of pain and region)
when inflammation spreads to surrounding peritoneum; at right inguinal region pain becomes localised and constant
what elicits pain in appendicitus
movement of hip joint, coughing
visceral source of subrapubic (hypogastric) pain
referred pain from hindgut structures, descending colon to anal canal
what level is suprapubic region
T12, L1-L2
visceral referred pain
stomach (T7-8), spleen (T10), kidney and ureter (T11-L2)
