Flashcards in 107-108b GI Motility Deck (17)
where is somatic innervation to GI system?
oropharynx and anal spinchter (skeletal muscle)
what are the GI Phases?
1) Cephalic- sense activate CNS for food
2) Gastic - stretch activates chemo- and mechanoreceptors; activates CNS and intrinsic reflexes to increase secretion and motility
3) Intestinal - chyme activates chemo- and mecanoreceptos; CNS and intrinsic; increases secretions
4) Interdigestive - migrating motor complexes that aren't felt
what electrical links GI smooth muscle cells?
what are slow waves?
periodic, spontaneous depolarizations of membrane potential that come close but don't trigger an AP (due to changes in Na perm)
what causes smooth muscle contrations?
slow wave + input from vagus or intrinsic plexus (stretch, ACh, parasympathetics); slow waves determine frequency and speed of progation for muscle contrations
when is the swallowing reflux triggered?
when the bolus reaches the pharynx
what is the main afferent for swallowing?
primary vs secondary peristalsis
primary is via CNS (vagus nerve); secondary is via intrinsic reflex or CNS reflex due to esophageal stretch
proximal stomach - gastric motor activity storage
no slow waves or rhythmic contractions
active inhibition following swallowing --> receptive relaxation via the vagus
where does grinding and mixing occur? what causes it?
where go GI sympathetics go after the sympathetic chain?
how do sympathetics and parasympatherics affect the GI system
via modulating the enteric nervous system
what can cause hyperpolarization of GI smooth muscle and thus stop contractions?
what is the slow wave pacemake in the gut?
efferents involved in swallowing?
do solids or liquids leave the stomach first?