Phys GI motility Flashcards
Connections between smooth muscle cells
nexus. means propagation without nerves
nature of chewing
stretch reflex
UES vs LES
UES is an anatomical sphincter
LES is not
Pressures in esophagus during swallowing
5 items
above 0 at UES, dropping, then rising in swallow
above 0 high up, including neck
below 0 in thorax, positive during swallowing
above 0 at & below diaphragm
above 0 at LES, lowers upon swallowing for entry
primary peristaltic wave
swallowing
secondary peristaltic wave
sth stuck in throate
distribution of muscle fiber types in esophagus
upper 1/3 striated
middle 1/3 transition (both)
lower 1/3 smooth (unaffected by vagotomy)
myogenic tone of sphincters
closed. NO from stimulus relaxes
location of oxyntic glands
stomach body
location of antrum
bottom by pylorus
pressure of stomach during swallow
drops to allow entry of food
gastric motility
wave goes down to pylorus increasing intensity, maintaining frequency
movement of food in stomach
most is squished back up (retropulsion)
very little pushed through pylorus
Need spikes for stomach contraction wave?
no, determined by height of plateau. spikes increase intensity
frequency of stomach contraction
3-5/min
3 things that reduce gastric emptying?
fat
acid
hyper/hypotonic solution
fastest emptying thing from stomach
isotonic water
SI motor pattern
irregularly spaced waves for stegmental mixing. no propagation
actions of SI
mixing
digestion
absorption
migrating motor complex
every 90 min in unfed SI (“housekeeper reflex”)
initiated by motolin (from neurons)
effect of motolin
migrating motor complex
source of electrical stimulus in gut
interstitial cells of Cajal
trigger of contraction in stomach and SI
Stomach: waves
SI: needs action potential - spiking on top of slow wave. frequency can approach slow waves, but not exceed it. not propagated.
colon features
haustra (bubbles) teniae coli (longitudinal muscle bands)
Ileocecal sphincter actions
control center
relaxation upon ileal distension
contraction on colonic distention
tonic resting contraction
controlled in the wall of the gut
mass movement
haustrations disappear in colon, sht moves, several times a day.
achalasia
failure to relax esophageal sphincter
megacolon
failure to relax rectal sphincter (absence of ganglion?)
