gastric motility

Question 1

What kind of accommodation does the stomach exhibit when food enters?

Answer 1

receptive relaxation due to the swallowing refulx and response to gastric mechanorecrpots

Question 2

What NT are released during receptive relaxation?

Answer 2

ACH-VIP/NO, maybe something else?

Question 3

What effect does the dorsal vagal complex have in response have during a meal?

Answer 3

a minor one

Question 4

What is the Gastrocolic reflex

Answer 4

induces the need to defecate after ingesting a meal

Question 5

What is the Gastroileal reflex

Answer 5

causes ileoceccal valve to relax transfer contents from small to large bowel

Question 6

What is the optimal pH for gastric lipase? What does it do?

Answer 6

pH 3-6, produces free fatty acids

Question 7

Is there active transport in the stomach?

Answer 7

no, only absorbed by diffusion-alcohol and aspirin

Question 8

The emptying of liquids in the stomach uses?

Answer 8

the proximal stomach using tonic contractions and the pyloris opens partially in response to feedback from the duodenum

Question 9

the empyting of solids in the stomach uses?

Answer 9

antral stomach pump uses phasic contractions driven by basal electrical rhythm to grind the meal

Question 10

How big must the food be to passs through the pyrolus?

Answer 10

<2mm

Question 11

What does the peristalsis occur at?

Answer 11

basic electrical rhythm- 3-5 min

Question 12

How can amplitude of the BER be changed?

Answer 12

neural (aCH causes Ca influx) and hormonal (gastrin)

Question 13

What determines the magnitude of contraction in the stomach?

Answer 13

number of AP on the crests of the slow waves determines the magnitude of contraction

Question 14

What happens to the contractions are they get closer to the pyloric sphincter?

Answer 14

they speed up and strengthen

Question 15

Does sugar or a solid meal empty the stomach faster>

Answer 15

sugar!

Question 16

What inhibits gastric contractions adn emptying>

Answer 16

acid in the duodenum(enteric/vagal or hormonal secretin ad somatostatin), fat in the duodenum via CCK, osmolality of duodenal contents via enteric neural mechanisms (maybe hormones)

Question 17

What does konjac flour do?

Answer 17

delays gastric empyting, keeps you fuller longer

Question 18

What are the feedback mechanisms from the SI to the stomach?

Answer 18

nutrients- postive feedback to the fundus to relax, pylorus to contract, neg feedback to the antrum which grinds the food

Question 19

When does the MMC work?

Answer 19

during fasting

Question 20

What is phase 1 of the MMC>

Answer 20

Phase I: Quiescence

20-60 minutes

Question 21

What is phase 2 of the MMC>

Answer 21

Phase II: Irregular,
Peristaltic Contractions
10-30 minutes
Increase in gastric, pancreatic juices

Question 22

What is phase 3 of the MMC

Answer 22

Phase III: FASTING! 
Intense Contractions
5-10 minutes
Pylorus opens fully
Stimulated by some
	prokinetic drugs
Benzoar hairball?

Question 23

What is pyloric stensos

Answer 23

congenital condition where pylorus fails to relax after a meal leading to malnutrition and dehydration. Treated with surgical myotomy.

Question 24

What is Gastroparesis? what is it due to?

Answer 24

delayed gastric empyting due to DM neuropathy (and surgery,drugs, cancer), the vagus and enteric nerves fail to generate enough force to empty the stomach

Question 25

what do you treat Gastroparesis with?

Answer 25

prokinetic drugs- cisapirzide or metocloproamie

Question 26

what is Dumping Syndrome

Answer 26

rapid gastric emptying usually due to gastric by pass, high sugar meals.

Question 27

How does the body deal with dumping syndrome?

Answer 27

water moves into the lumen resulting in hypovolemia and reduced blood pressure. Results in nausea, weakness, dizziness, sweating, shakiness, diarrhea, heart palpitations

Question 28

how does Peptic ulcer disease lead to abnormal motility

Answer 28

scarring and ulcers near the pylorus can delay emptying or in duodenal ulcers can lead to rapid gastric emptying due to loss of duodenal negative feedback mechanisms.

Question 29

What are some causes of vomiting

Answer 29

gastritis, poisoning, brain tumors, increased intracranial pressure, migraine, vestibular problems, bowel obstruction

Question 30

What is regurgitation?

Answer 30

the return of undigested food (that has not yet reached the stomach) back up the esophagus to the mouth.

Question 31

What are sensors for vommiting?

Answer 31

phaynx, higher centers, vestibular info, irritants of blockage of GI tract, blood born elements

Question 32

What does the parasympathetics due in response to vommiting?

Answer 32

increase salivation (bicarb) to protect teeth

Question 33

Where does retro-peristalsis start?

Answer 33

middle of small intestine

Question 34

What can happen before vomiting>

Answer 34

retching- inspiration against a closed glottis

Question 35

What is the mecahnism of vomiting?

Answer 35

glottis closes, hyoid moves up and forward opening the UES, diaphragm and ab muscle contracts moving food into esophagus as LES relaxes

Question 36

Does the stomach contract during vomiting?

Answer 36

NO, just the annular notch

Question 37

Does the esophagus retroperistalsis during vomiting>

Answer 37

no, all control is mediated by extrinsic nerves

Question 38

What are NT that are inhibited to control vomiting?

Answer 38

dopa, histamine, and serotonin