Physiology: gastric motility and secretion

Question 1

describe how the stomach produces chyme

Answer 1

mixes the food with gastric secretions to produce semi-liquid chyme

Question 2

what type of digestion is the stomach the starting point for, and what by

Answer 2

protein digestion

by pepsin and HCl

Question 3

what type of digestion is continued by the stomach, from the oesophagus, and what by

Answer 3

carbohydrate digestion by salivary amylase

Question 4

describe the mechanical activity of the orad region of the stomach

Answer 4

tonic(maintained)

Question 5

describe the mechanical activity of the caudad region of the stomach

Answer 5

phasic(intermittent)

Question 6

when does relaxation of the orad region of the stomach occur

Answer 6

during a swallow, allowing storage of ingested material

Question 7

describe the slow wave activity of the orad and caudad regions of the stomach

Answer 7

orad = no slow waves 
caudad = slow waves occur continuously, but only those reaching threshold incur contraction

Question 8

describe the function of tonic contractions in the orad region of the stomach

Answer 8

propels contents to caudad region intermittently, contractions are weak and short lived(1min)

Question 9

what effect does gastrin have on stomach contractions and emptying

Answer 9

decreases contraction, and therefore rate of stomach emptying

Question 10

describe the function of the Antral wave

Answer 10

propels contents from caudad region towards pylorus, through which a very small volume of chyme flows into duodenum

Question 11

describe the action of retropulsion

Answer 11

velocity of contraction increases towards the pyloric junction, chyme rebounds against constricted distal antrum back into relaxed body of stomach

Question 12

what is the function of retropulsion

Answer 12

mixes gastric contents reducing chyme to small particles that pass through the pylorus