VI-Intro GI Flashcards
effect of Ach
from parasymps so vasodilate, inc secretions, smooth muscle contract
norepinephrine effects
also epinephrine and dopamine from symps so vasoconstrict, inhibit smooth muscle contract, dec secretins
serotonin function
sensory, interneurons
NO effects
smooth muscle relaxation
VIP
vasoactive intestinal peptide
smooth muscle relaxation
basal electrical rhythm
aka slow waves, at rest
-initiated by interstitial cells of cajal (pace maker cells)
no contractions
spike potentials
rapid depolarization at peak of slow waves to elicit contractions
-stimulated by Ach, inhibited by VIP and NO
migrating motor complex
MMC
during interdigestive period every 90 min to maintain directional movement of contents
-strongest contractions in upper GI then fade
is loss of function then inc bacterial infection
LES regulates
food into stomach
-lower esophageal sphincter
PS regulates
gastric emptying
-pyloric sphincter
IS regulates
by relaxing when ileum distends or contracting when ascending colon distends
ileocecal sphincter
IAS regulates
relaxation when rectum distends
-internal anal sphincter
EAS regulates
relaxing for defecation or contracting when not desired
-external anal sphincter
CCK stimulates
decrease emptying
-triggered by fat in duodenum
gastrin stimulates
dec emptying
triggered by protein in stomach
