Lecture 4 (A) - Abdominal nerves and perception of visceral pain Flashcards
What is the ENS?
- Considered the brain of the gut
- Composed of more than 100million intrinsic neurones that extend the majority of the GI tract from the oesophagus to the anus
- Enable the GI tract to perform its basic reflex functions of secretion, absorption, mixing and gut movements
- Can function without the input of the CNS/ANS (although they work together to modulate GI tract function)
How is the ENS arranged?
Arranged into ganglionate plexuses with interconnecting bundles of unmyelinated nerve fibres. The axons of the intrinsic ENS neurones project to sympathetic ganglia, the pancreas, gall bladder, trachea, spinal cord and brain.
Where do sympathetic nerves arise from?
T1-L2
What do the splanchnic nerves do?
Relay visceral sensations - involved in pain.
Where do the splanchnic nerves arise from?
T5-12
Greater splanchnic nerve - T5-9
Lesser splanchnic nerve - T10-11
Least splanchnic nerve - T12
Where do parasympathetic nerves arise from?
Arises from cranial nerves 2, 7, 9 and 10 in the brainstem as well as sacral spinal cord region S2-4.
Which cranial nerves are part of the parasympathetic autonomic nervous system?
- Oculomotor
- Facial
- Glossopharyngeal
- Vagus
What is a plexus?
An interconnecting network of nerves (or vessels in some cases).
Where do autonomic nerves to the abdomen form plexuses?
Surrounding the aorta and its branches.
Where do the nerves running alongside the coeliac artery arise from?
T5-9 (S) and X (PS)
Where do the nerves running alongside the superior mesenteric artery arise from?
T10-11 (S) and X (PS)
Where do the nerves running alongside the renal arteries arise from?
T10-12 (S) and X (PS)
Where do the nerves running alongside the testicular/ovarian arteries arise from?
T10-11 (S) and X (PS)
Where do the nerves running alongside the inferior mesenteric artery arise from?
T12-L2 (S) and S2-4 (PS)
Where do the nerves forming the superior and inferior hypogastric plexuses arise from?
T12-L2 and S2-4
