GI Motility

Question 1

Receptive relaxation

Answer 1

in response to swallowing, stomach muscle relax to accommodate large volume of meal

Question 2

Three major motor functions of the stomach

Answer 2

1. receptive relaxation
2. mixing and propulsion facilitates digestion solubilizing and reducing the size of the particles
3. gastric emptying at a regulated rate to release gastric chyme into the duodenum

Question 3

Dumping Syndrome

Answer 3

Gastric emptying is too fast, duodenal ulcer may be resulted

Question 4

Gastroparesis

Answer 4

Gastric emptying is too slow, vomiting and nausea

Question 5

Regulation of gastric emptying

purpose, stimuli, receptor

Answer 5

Purpose: give time to neutralize acidic chyme in the duodenum , digest and absorb nutrients
Stimuli: distension caused by food bolus, osmolarity pH lipid content
Receptor: at stomach and duodenum**

Question 6

Gastric emptying regulation at duodenum
Stimulation 
1. fat ---- ? cell----?
2. H+ ----? cell ----?
3. ?
increase ? contraction
decrease ? contraction
Result : decrease gastric emptying

Answer 6

1. Fat ---> K cell---> GIP 
Fat ---> I cell ---> CCK
2. H+ ---> S-cell ---> secretin
3. Distention hyperosmotic
increase pyloric sphincter contraction
decrease antral contraction

Question 7

Types of GI movement

Answer 7

1. peristalsis
2. segmentation
3. Tonic vs phasic contraction
4. migrating motor complex

Question 8

Peristalsis definition

Answer 8

successive contraction coordinated along a substantial length of the gut that serves conspicuous propulsion function

Question 9

Segmentation

Answer 9

non-propulsive annular, neither preceded nor followed by other contractions, for mixing purposes

Question 10

Tonic vs phasic contraction

Answer 10

Tonic: found in GI tract sphincter, aids the mixing of luminal content and allows it to pass at proper times
spasm is pathological complete tonic contraction elsewhere in the gut

Tonic: Slow wave, spontaneous depolarization and repolarization, Ca2+ and K+ forms basal electrical rhythm, determine rate of GI motility