107-108b GI Motility Flashcards Preview

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Flashcards in 107-108b GI Motility Deck (17):
1

where is somatic innervation to GI system?

oropharynx and anal spinchter (skeletal muscle)

2

what are the GI Phases?

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

3

what electrical links GI smooth muscle cells?

gap junctions

4

what are slow waves?

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

5

what causes smooth muscle contrations?

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

6

when is the swallowing reflux triggered?

when the bolus reaches the pharynx

7

what is the main afferent for swallowing?

recurrent layrngeal

8

primary vs secondary peristalsis

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

9

proximal stomach - gastric motor activity storage

no slow waves or rhythmic contractions
active inhibition following swallowing --> receptive relaxation via the vagus

10

where does grinding and mixing occur? what causes it?

antrum
distension

11

where go GI sympathetics go after the sympathetic chain?

celiac ganglion
SMG
IMG

12

how do sympathetics and parasympatherics affect the GI system

via modulating the enteric nervous system

13

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

NE
sympathetics

14

what is the slow wave pacemake in the gut?

mid-deodenum

15

efferents involved in swallowing?

glossopharyngeal
trigeminal
vagus
sympathetics

16

do solids or liquids leave the stomach first?

liquids

17

peristalis

contraction with a leading wave of distention via enteric circuits