107-108b GI Motility Flashcards

1
Q

where is somatic innervation to GI system?

A

oropharynx and anal spinchter (skeletal muscle)

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2
Q

what are the GI Phases?

A

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

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3
Q

what electrical links GI smooth muscle cells?

A

gap junctions

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4
Q

what are slow waves?

A

periodic, spontaneous depolarizations of membrane potential that come close but don’t trigger an AP (due to changes in Na perm)

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5
Q

what causes smooth muscle contrations?

A

slow wave + input from vagus or intrinsic plexus (stretch, ACh, parasympathetics); slow waves determine frequency and speed of progation for muscle contrations

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6
Q

when is the swallowing reflux triggered?

A

when the bolus reaches the pharynx

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7
Q

what is the main afferent for swallowing?

A

recurrent layrngeal

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8
Q

primary vs secondary peristalsis

A

primary is via CNS (vagus nerve); secondary is via intrinsic reflex or CNS reflex due to esophageal stretch

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9
Q

proximal stomach - gastric motor activity storage

A

no slow waves or rhythmic contractions

active inhibition following swallowing –> receptive relaxation via the vagus

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10
Q

where does grinding and mixing occur? what causes it?

A

antrum

distension

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11
Q

where go GI sympathetics go after the sympathetic chain?

A

celiac ganglion
SMG
IMG

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12
Q

how do sympathetics and parasympatherics affect the GI system

A

via modulating the enteric nervous system

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13
Q

what can cause hyperpolarization of GI smooth muscle and thus stop contractions?

A

NE

sympathetics

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14
Q

what is the slow wave pacemake in the gut?

A

mid-deodenum

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15
Q

efferents involved in swallowing?

A

glossopharyngeal
trigeminal
vagus
sympathetics

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16
Q

do solids or liquids leave the stomach first?

A

liquids

17
Q

peristalis

A

contraction with a leading wave of distention via enteric circuits