Normal Gastric Motility, Gastric Dysmotility

Question 1

Neuronal action for stomach storage

Answer 1

receptive relaxation induced by swallowing –> induced vagal response

Question 2

Neuron action for stomach accomodation

Answer 2

gastric mechanoreceptors, vagovagal response

Question 3

What is the gastric pacemaker and where is it?

Answer 3

interstitial cell of cajal –> proximal body along greater curvature

Question 4

What are gastric slow waves?

Answer 4

internal rhythm of the stomach –> 3/minute

Question 5

What is the contraction threshold?

Answer 5

the electric threshold that must be reached before the stomach begins contracting

Question 6

What is the maximum contraction frequency of the stomach?

Answer 6

30/minute

Question 7

Functions that occur during the postprandial phase in the stomach

Answer 7

trituration: mixing and retropulsion

Question 8

What pressure gradient allows for emptying of liquid in stomach?

Answer 8

antroduodenal gradient (from gastric tone)

Question 9

How do solids empty from the stomach?

Answer 9

chyme via pyloric pump

Question 10

Faster or slower gastric emptying? larger volume of food

Answer 10

faster

Question 11

Faster or slower gastric emptying? liquids

Answer 11

faster

Question 12

Faster or slower gastric emptying? starch

Answer 12

fastest

Question 13

Faster or slower gastric emptying? protein

Answer 13

starch > protein > fat

Question 14

How is the pyloric pump regulated?

Answer 14

duodenal neuronal and hormonal feedback due to 1. too much acid, 2. high protein or fat, 3. excessive chyme volume, 4. hypertonic fluid

Question 15

3 nervous reflexes of stomach/duodenum

Answer 15

1. inhibitory vagal efferent (in vagovagal reflex)
2. duodenal feedback
3. inhibitory sympathetic nerves

Question 16

4 hormones that provide negative feedback from duodenum to stomach

Answer 16

CCK, somatostatin, dopamine, secretin

Question 17

Fasting phase motor movements in stomach

Answer 17

about 2 hours:
long phase I: no contractions
short phase II: few irregular contractions
brief phase III: intense contractions (house keeping function, motilin)

Question 18

gastroparesis

Answer 18

impaired transit of food from stomach to duodenum –> mechanical obstruction excluded

Question 19

Diabetic gastropathy

Answer 19

common in type 1, usually associated with autonomic neuropathy

(delayed emptying, rapid emptying, bezoar formation, malnutrition)

Question 20

clinical presentation of gastroparesis

Answer 20

nausea, vomiting, early satiety, abdominal distension/pain postprandial

Question 21

Mgmt of gastroparesis

Answer 21

small/frequent meals, low-fat/residue diet, glucose control, prokinetic agents, antimimetics, gastric electric stimulation, surgery

Question 22

Prokinetics

Answer 22

dopamine antagonists, motilin agonists, muscarinic agonists, AChE inhibitors, opioid antagonists, CCK antagonists, serotonin agonist

• need to know metoclopramide (dopamine), domperidone (dopamine), erythromycin (motilin)

Question 23

Side effects of metoclopramide

Answer 23

prolactin, tardive dyskinesia, arrhythmia

Question 24

Side effects of domperidone

Answer 24

prolactin, arrhythmia

Question 25

Side effects of erythromycin

Answer 25

cramping, nausea, vomiting, interaction with CYP3A inhibitors

Question 26

Dumping syndrome

Answer 26

rapid gastric emptying of hypertonic liquids often seen in gastrojejunostomy –> nausea, flushing, dirrhea, syncope, ultimately hypoglycemia

Question 27

Non-ulcer dyspepsia

Answer 27

following sypmotoms referable to UGI –> post prandial distress syndrome (bothersome fullness) or epigastric pain

• symptoms for >3 mos. and onset >6mos. before diagnosis

Question 28

Up to ___% of NUD have delayed gastric emptying

Answer 28

45% –> gastric dysrhythrmias and poor gastric compliance, or ineffective antropyloroduodenal contraction patterns

Question 29

Tx of NUD

Answer 29

PPI, prokinetics, gastric compliance enhancers, visceral perception blockers, psychological approaches