Neuromuscular control of gut motility Flashcards
What is VIP?
What is it’s function?
Vasoactive Intestinal Peptide
Inhibitory neurotransmitter
- keeps K+ channels open longer to increase
- decrease spike-mediated SMC contraction
In what histological layer is the myenteric plexus located?
Muscularis externa
Which parts of the gut have myenteric plexus?
From esophagus to rectum
Which parts of the gut have submucosal plexus
small and large intestines
What do plexuses regulate?
contraction of smooth muscle, secretion, and digestion
What is the major excitatory neurotransmitter in longitudinal smooth muscle? (for motility)
Acetylcholine
What are the major excitatory neurotransmitters for circular smooth muscle? (for motility)
Ach, Substance P, 5-HT (Serotonin)
What are the major inhibitory neurotransmitters?
VIP, NO, Purines
What is the excitatory neurotransmitter for glandular/exocrine release?
VIP
What is the parasympathetic innervation for the GIT?
Vagus (CN X) from pharynx to superior 2/3 of colon.
Sacral spinal nerves & pelvic nerves for distal 1/3 of colon and rectum.
What is the sympathetic innervation for the GIT?
Thoracic/lumbar spinal cord & associated pre-vertebral ganglia.
What happens with megacolon? (Hirschprung’s disease)
can’t open up internal anal sphincter
What is Shaga’s disease?
parasitic roundworm infection
How is parkinson’s related to GIT?
general motility effects
What is Achalasia?
can’t open up LES
