GI motility Flashcards
how many sphincters along the GI tract
7
increases the tone of the gut and the velocity and intensity of contractions.
exerts control primarily over digestive motility
myenteric plexus
involved with local conditions and controls local secretion, absorption, and muscle movements.
its principal role is in sensing the environment within the lumen
submucosal plexus
mass movements are long, slow powerful contractions that move over the colon 3 or 4 times per day, typically
after meals
buccal phase voluntary/involuntary
voluntary
pharyngeal phase voluntary/involuntary
involuntary
esophageal phase voluntary/involuntary
involuntary
sympathetic division acts through sympathetic nerves to
inhibit enteric nervous system
parasympathetic division acts primarily through the dorsal motor nucleus of the vagus nerve to
stimulate ENS activity
excitatory, stimulates smooth muscle contraction, increases intestinal secretions, release of enteric hormones and dilation of blood vessels
acetylcholine
derived from extrinsic sympathetic neurons and is almost always inhibitory and has the opposite effect of acetylcholine
norepinephrine
GI smooth muscle are linked electrically linked by
gap junctions
pacemaker cells that have the capacity to generate the basic electrical rhythm or slow wave activity
interstitial cells of cajal (ICCs)
upper esophageal sphincter is composed of _______ muscle
striated and circular
lower esophageal sphincter is composed of ______ muscle
smooth and longitudinal