Gastric motility

Question 1

What is gastroparesis?

Answer 1

Decreased gastric motility (NOT a total shut down)

Question 2

What is the migrating motor complex?

Answer 2

GI motor activity that starts in the stomach, and sweeps over the upper GI tract about every 90 minutes

Question 3

What happens to the migrating motor complex during the fed state?

Answer 3

No longer migrating–constant motor activity

Question 4

What are the three general types of GI motor activity?

Answer 4

Storing
Churning
Emptying

Question 5

What causes the storing effect of the GI tract?

Answer 5

Tonic contractions

Question 6

What are the two steps of gastric storing/filling?

Answer 6

Receptor relaxation

Gastric accommodation

Question 7

What happens during the receptive relaxation phase of gastric storing? (2)

Answer 7

Relaxation of LES and stomach in anticipated by food

Rise in gastric volume, without change in pressure

Question 8

What is the innervation of receptive relaxation reflex of the stomach?

Answer 8

Vagus

Question 9

What initiates the receptive relaxation of the stomach?

Answer 9

Swallowing

Question 10

What is the signalling used in receptive relaxation to relax the LES?

Answer 10

Non Cholinergic and nonadrenergic (NO mediated)

Question 11

What happens in gastric accommodation?

Answer 11

Stomach relaxation in response to gastric filling

Dilation of fundus

Question 12

What primarily regulates gastric accommodation? What modulates it?

Answer 12

ENS

Vagus

Question 13

What happens to volume/pressure in gastric accommodation?

Answer 13

Increase in volume without increase in pressure (just like the bladder)

Question 14

What are the three parts of gastric churning?

Answer 14

Propulsion
Retropulsion
Grinding

Question 15

What is propulsion part of gastric churning?

Answer 15

Movement of stomach contents against the pyloric region

Question 16

What happens to the pyloric sphincter during gastric churning?

Answer 16

Shuts down

Question 17

What initiates the propulsion part of gastric churning?

Answer 17

Pacemaker cells near the greater curvature of the stomach

Question 18

What is retropulsion part of gastric churning?

Answer 18

Pulverization and shearing of food particles by contractions

Question 19

What is the overall goal of gastric churning?

Answer 19

Increased surface area of food

Question 20

What happens in the grinding phase of gastric churning?

Answer 20

Food is trapped in the antrum

Question 21

When do particles larger than 2 mm pass into the duodenum?

Answer 21

Interdigestive period (2 hours later)

Question 22

The rate of gastric emptying is dependent on what?

Answer 22

The content of ingested material

Question 23

What happens to rate of gastric emptying with increasing protein and fat?

Answer 23

Lowers rate of emptying

Question 24

What controls the rate of gastric emptying?

Answer 24

Neuronal and hormonal control

Question 25

What three hormones play a role in gastric emptying?

Answer 25

1. Secretin 2. CCK 3. Gastrin

Question 26

What are the four NTs utilized in gastric emptying?

Answer 26

Ach NO 5HT VIP

Question 27

HCl in the duodenum stimulates what hormone to be secreted? Result?

Answer 27

Secretin = impaired gastric emptying, increase HCO3 production from the pancreas

Question 28

Fat in the duodenum primarily stimulates what hormone to be secreted? Result?

Answer 28

CCK --impaired gastric empyting

Question 29

Protein in the stomach stimulates what hormone to be secreted? Result?

Answer 29

Gastrin-- impaired gastric emptying

Question 30

Duodenal distension in the duodenum stimulates what? Result?

Answer 30

ENS--impaired gastric emptying

Question 31

Vagal stimulation in the duodenum stimulates which three neurotransmitters that impair gastric emptying?

Answer 31

Ach, opioid, 5HT = impaired gastric emptying

Question 32

What are the four targets of CCK?

Answer 32

Gallbladder Pancreas Stomach Sphincter of Oddi

Question 33

What is the effect of CCK on the gallbladder?

Answer 33

Contraction

Question 34

What is the effect of CCK on the pancreas?

Answer 34

Acinar secretion

Question 35

What is the effect of CCK on the the stomach?

Answer 35

Reduced emptying

Question 36

What is the effect of CCK on the sphincter of Oddi??

Answer 36

Relaxation

Question 37

Gastroparesis is frequently associated with what?

Answer 37

Impairments of the pyloric region or pyloric sphincter itself (DM neuropathy/ infantile pyloric stenosis)

Question 38

What are the events involved in emesis?

Answer 38

Afferent fibers activated, which trigger the vomiting center, causing a reverse wave of peristalsis

Question 39

What is the stimulus for an emetic response?

Answer 39

Irritation of the GI mucosa

Question 40

What are the nerve fibers activated in emesis?

Answer 40

Afferent fibers

Question 41

What is the purpose of increased saliva prior to emesis?

Answer 41

Lubricates Increases pH Mucin protection

Question 42

The emetic response is coordinated by what nerve?

Answer 42

Vagal afferents and emetic center of the brain

Question 43

What is the purpose of secondary peristalsis in emesis?

Answer 43

Returns esophageal material back to the stomach

Question 44

What are the two stimuli for secondary peristalsis?

Answer 44

Stretch and lower pH

Question 45

What are the four key neurotransmitters for sensory information from the gut to be relayed back to the CNS?

Answer 45

5-HT, Ach, histamine, and D2

Question 46

What muscarinic receptors are located in the chemoreceptive trigger zone?

Answer 46

M1

Question 47

Motion sickness is mediated through what two receptors on the cerebellum?

Answer 47

Histamine and Ach

Question 48

Why can uncontrolled DM lead to gastroparesis?

Answer 48

Neuropathy

Question 49

What is the key neurotransmitter in the intestines?

Answer 49

5HT

Question 50

What happens in retching?

Answer 50

occurs when the upper esophageal sphincter does not relax and the contents of the stomach are not expelled

Question 51

What are the three receptors in the chemoreceptor trigger zone (which stimulates the emetic center of the brain)?

Answer 51

5HT, D2, M1

Question 52

What are the neurotransmitter receptors on the NTS (which stimulates the emetic center of the brain)?

Answer 52

5HT D2 M1 H1

Question 53

Vagal stimulation in the duodenum stimulates which two hormones that promote gastric emptying

Answer 53

NO, VIP = promotes gastric emptying