motility Flashcards
what are the 3 layers of muscle in the stomach
outer- longitudinal
circular
oblique
what is the nerve supply of the myenteric plexus
p’symp via the vagus
symp via the coeliac ganglion
what is the sensory afferent for the stomach
vagal and splanchnic nerves
what are the layers of the stomach wall
epithelia mucosa lamina propria muscularis mucosae submucosa subnmucosal plexus muscularis externa and myenteric plexus
what is receptive relaxation
distension of the lower oesophagus induces relaxation of the orad
what is the vagovagal reflex
mechanoreceptors relay information to the CNS
VIP is released for vagal nerves causing orad relaxation on swallowing food or on distension of the stomach
what are the movement patterns of the stomach
propulsion
grinding
retropulsion
what is the slow wave frequency of the stomach
3-5 per min
what does neural and hormonal input effect
action potential frequency but not slow wave frequency
what hormones increase action potential frequency and force of contraction
gastrin and motilin and p’symp
what hormone decreases action potential frequency
secretin and symp
what hormone mediates migrating myoelectric complexes
motilin (endocrine cells)
how often do MMCs happen
90 mins
how long does it take to empty the stomach
3 hours
how small must solid particles be before they are released
less than 1 mm3
what hormone inhibits gastric emptying in the presence of fat
cholecystokinin
what effect does protons have on gastric emptying
inhibits-
detected by duodenum and relayed to stomach via the myenteric plexus
what neurotranmitters does the p’symp ns use in the intestine
ach and motilin via the vagus
what neurotranmitter does the symp ns use in the intestine
noradrenaline via the coeliac and superior mesenteric ganglia
what is the slow wave frequency in the duodenum
12
what is the slow wave frequency in the ileum
9 per minute
how are contranctions in the small intestine coordinated
ENS
what hormones in the gut cause orad contraction
ach and substance P
what hormones in the gut cause caudad relaxation
VIP and nitric oxide
what is the p’symp supply of the colon
vagus up to the transvers colon
pelvic nerves for sigmoid- anal canal
what reflexes cause mass movements in the colon
gastrocolic and duodenocolic
what is the gastrocolic reflex
distension of the stomach increases motility in the colon
what mediates the two limbs of the gastrocolic reflex
p’smyp ns - afferent
efferent- CCk and gastrin
describe emesis
- Reverse peristalsis in small intestine
- Relaxation of the stomach and pylorus
- Forced inspiration to increase abdominal pressure
- Relaxation of the lower oesophageal sphincter
- Forceful expulsion of gastric and duodenal contents
somatostatin - delta cells
inhibits glucagon and insulin release
