Neuronal Regulation of GI Tract Flashcards
Myentric Plexus is responsible for
Motor pattern of mixing or peristaltic movement
Regulates activity of the muscularis externa
Subumucosal plexus is responsible for
The function of the mucosa: especially absorptive and secretory activities of intestinal epithelial cells
Three structures required for function of intestinal motility patterns
- Intestinal smooth muscle
- Myenteric plexus
- Autonomic nervous system
nb: ANS is not required for myenteric FIRING
Rank the action potential firing rates for stomach, small intestine and large instine
small intestine > large intestine > stomach
When do small intestine action potentials fire?
On top of the slow waves
nb: slow waves generated by interstitial cells of Cajal
Sympathetic actions of ENS
Anti-digestive
Anti-nutrient absorption
Pro-fluid and e’lyte absorption
Anti-motility
Parasympathetic actions of ENS
Pro-digestive
Pro-nutrient absorption
Pro-fluid and e’lyte secretion
Pro-motility
How do GVA fibers reach the medulla from the GI tract?
Via the Vagus and Pelvic Splanchnic Nerves
How do pain (GSA) fibers reach the brain?
Travel along the sympathetic nervous nerves
nb: GSA fibers ARE NOT sympathetic fibers
GI motility is mostly regulated by
Enteric Nervous System
Role of dopamine on gut motility?
Increases transit time
anti-kinetic
Role of 5-HT (Serotonin) on gut motility?
Speeds up transit time
pro-kinetic stimulates asymmetric motility patterns
Role of ACh on gut motility?
Speeds up transit time
stimulates smooth muscle contraction
Role of Somatostatin on gut motility?
Speeds up transit time
inhibits inhibitory motility interneurons
Role of GABA on gut motility?
Slows down transit time
Inhibits pro-motility interneurons
