DDSEP Gastric motility Flashcards
What nerve induces gastric relaxation?
What happens with lacerating this nerve?
Vagus.
Vagotomy will cause accelerated emptying of liquids and interferes with antral contractile activity which will reduce breakdown and delay emptying of solids.
Need pyloroplasty if done intentionally.
What are the migrating motor complexes?
MMC’s are 3 phases where you have quiescence, then intermittent pressure activity, then activity front where stomach and small bowel coordinate contraction at highest frequencies.
MMC is the intestinal housekeeper.
What activates and inhibits the MMC’s?
Meals inhibit this, but it cycles in fasting state day and night.
End of phase 2 and during phase 3 there is pancreaticobiliary secretions and GB emptying
What is the SIP syncytium?
Neural network of the stomach. The pacing of antral contraction is set by pacemaker in the greater curve (removed during sleeve procedure)
What determines the kinetics of emptying?
Solid vs. liquid (liquid half life 30 minutes)
Higher nutrient content the slower it empties.
What are the phases of gastric emptying?
What happens to everything left over?
Initial lag phase where food is mechanically digested into smaller particles (trituration) then a linear phase where these particles are emptied.
Anything leftover (large indigestible solids) are swept by the housekeeping MMC phase III
What is the mechanism of action for semaglutide (Wegovy)
GLP-1’s are hormones which will:
1. Slow gastric emptying
2. Stimulate insulin release/suppress glucagon secretion in the pancreas
3. Suppress appetite in the brain
DPP-4’s will rapidly metabolize GLP-1’s, so synthetic GLP-1’s like wegovy cannot be metabolized by DPP-4 so they last substantially longer
What are the SB motility patterns?
Fed state- segmented non-propagated peristalsis simultaneously at multiple levels along the intestines (4-6 hours after eating)
4-6 hours after eating you get the fasting MMC pattern
What is the local peristaltic reflex?
A bolus in the lumen of the SB stimulates mucosal afferent nerves above the bolus with excitatory NT’s (AcCh/Substance P) and below it inhibitory NT’s like NO and VIP
What is the ileal brake?
It is where fat content in the ileum delays gastric emptying (via GLP-1, peptide YY etc)
On what test can you catch regurgitation?
Prolonged post-prandial esophageal manometry testing with impedance testing.
You see increase from baseline in intragastric pressures >30mm Hg followed by retrograde flow of contents back to the UES
What tests can you use on children and pregnant women for identifying delayed gastric emptying?
13C-Spirulina Gastric Emptying Breath Test (GEBT) which is a breath test measuring when the 13C gets into lungs
Wireless motility capsule which doesn’t empty with food due to size but is cleared by MMC phase III (5 hours = delayed)
