Gastric motility Flashcards
What is gastroparesis?
Decreased gastric motility (NOT a total shut down)
What is the migrating motor complex?
GI motor activity that starts in the stomach, and sweeps over the upper GI tract about every 90 minutes
What happens to the migrating motor complex during the fed state?
No longer migrating–constant motor activity
What are the three general types of GI motor activity?
Storing
Churning
Emptying
What causes the storing effect of the GI tract?
Tonic contractions
What are the two steps of gastric storing/filling?
Receptor relaxation
Gastric accommodation
What happens during the receptive relaxation phase of gastric storing? (2)
Relaxation of LES and stomach in anticipated by food
Rise in gastric volume, without change in pressure
What is the innervation of receptive relaxation reflex of the stomach?
Vagus
What initiates the receptive relaxation of the stomach?
Swallowing
What is the signalling used in receptive relaxation to relax the LES?
Non Cholinergic and nonadrenergic (NO mediated)
What happens in gastric accommodation?
Stomach relaxation in response to gastric filling
Dilation of fundus
What primarily regulates gastric accommodation? What modulates it?
ENS
Vagus
What happens to volume/pressure in gastric accommodation?
Increase in volume without increase in pressure (just like the bladder)
What are the three parts of gastric churning?
Propulsion
Retropulsion
Grinding
What is propulsion part of gastric churning?
Movement of stomach contents against the pyloric region
What happens to the pyloric sphincter during gastric churning?
Shuts down
What initiates the propulsion part of gastric churning?
Pacemaker cells near the greater curvature of the stomach
What is retropulsion part of gastric churning?
Pulverization and shearing of food particles by contractions
What is the overall goal of gastric churning?
Increased surface area of food
What happens in the grinding phase of gastric churning?
Food is trapped in the antrum
When do particles larger than 2 mm pass into the duodenum?
Interdigestive period (2 hours later)