IBSS 1532 Exam 1 Part 2– Questions With Expert
Solutions
What are the functions of the orad vs caudal stomach? Correct
Answer - the orad accepts ingested material and stores chyme
while the caudad mixes the chyme and regulates the rate of
emptying
What is receptive relaxation? Correct Answer - the immediate
muscle relaxation that occurs in the fundus of the stomach at the
initiation of a swallow
What ist he function of the peristaltic contractions of the caudad of
the stomach? Correct Answer - they mix food, reduce particle
size as they propel the stomach contents toward the pylorus
Is receptive relaxation in the stomach a long or short reflex?
Correct Answer - it is a long neural reflex
What kind of innervation/neurotransmitter release enables the
smooth muscles of the fundus to relax in receptive relaxation?
Correct Answer - nitric oxide released by enteric inhibitory
motor neurons
What are sieving vs retropulsion contractions in gastric emptying?
Correct Answer - sieving involves stomach contractions allowing
only small particles to enter the duodenum from the pyloris. Then,
retropulsion pushes larger contents back into the stomach, which
breaks them into smaller and smaller particles
What ist he effect on gastric emptying when the orad stomach is
distended? Correct Answer - the rate is increased
,What is the effect on gastric emptying when the strength of the
peristaltic contractions of the caudad stomach is increased?
Correct Answer - the rate is increased
What is the effect of the parasympathetic vs sympathetic nervous
system on the peristaltic contractions of the orad stomach?
Correct Answer - parasympathetic: increase contractinos/gastric
emptying
sympathetic: decrease contractions/gastric emptying
What is the effect of the presence of acidic chyme in the duodenum
on gastric emptying? How? Correct Answer - it decreases the
rate of gastric emptying by releasing secretin
What is the effect of fat digestion in the duodenum on the rate of
gastric emptying? How? Correct Answer - it decreases gastric
emptying by secreting CCK
What is the effect of hypertonic chyme in the duodenum on the rate
of gastric emptying? Correct Answer - it decreases it
What is the effect of secretin on gastric emptying? Correct Answer
- it decreases it
What is the effect of CCK on the rate of gastric emptying? Correct
Answer - it decreases it
Via which mechanism does distention of the duodenum and
hypertonic chyme cause a decrease in gastric emptying? Correct
Answer - inhibitory enteric nerves in a short reflex
Which three cells in the gastric mucosa modulate HCl secretion?
Correct Answer - G cells, D cells, and ECL cells
, What do the G cells in the stomach do? Correct Answer - they
secrete gastrin
What doe the D cells in the gastric mucosa secrete? Correct
Answer - somatostatin
What do the ECL cells in the gastric mucosa secrete? Correct
Answer - histamine
Which cells in the stomach secrete HCl? Correct Answer -
parietal cells
In the secretion of HCl by the stomach, what causes H+ to move from
the parietal cell into the stomach lumen? Correct Answer - it is
transported out of the cell through an H-K ATPase that allows K+ to
enter the cell as H+ leaves
What process within the gastric parietal cell forms a proton that will
eventually be pumped into the lumen to form HCl? Correct
Answer - carbonic anhydrase forms H2CO2, which then breaks
down into the H+ and bicarbonate ions
What is the function of bicarbonate in HCl secretion in the stomach?
Correct Answer - the bicarbonate is exchanged into the tissue for
the influx of a Cl ion and enters venous blood
What is the function of Cl in HCl secretion in the stomach? Correct
Answer - as bicarbonate is pumped out of the parietal cell, Cl
enters, traverses the cell, and exits into the stomach lumen via a
channel on the opposite side
What is the rate limiting step in the secretion of HCl by parietal
cells? Correct Answer - the availability of ATP that powers the
H-K ATPase that pumps H+ into the stomach lumen
Solutions
What are the functions of the orad vs caudal stomach? Correct
Answer - the orad accepts ingested material and stores chyme
while the caudad mixes the chyme and regulates the rate of
emptying
What is receptive relaxation? Correct Answer - the immediate
muscle relaxation that occurs in the fundus of the stomach at the
initiation of a swallow
What ist he function of the peristaltic contractions of the caudad of
the stomach? Correct Answer - they mix food, reduce particle
size as they propel the stomach contents toward the pylorus
Is receptive relaxation in the stomach a long or short reflex?
Correct Answer - it is a long neural reflex
What kind of innervation/neurotransmitter release enables the
smooth muscles of the fundus to relax in receptive relaxation?
Correct Answer - nitric oxide released by enteric inhibitory
motor neurons
What are sieving vs retropulsion contractions in gastric emptying?
Correct Answer - sieving involves stomach contractions allowing
only small particles to enter the duodenum from the pyloris. Then,
retropulsion pushes larger contents back into the stomach, which
breaks them into smaller and smaller particles
What ist he effect on gastric emptying when the orad stomach is
distended? Correct Answer - the rate is increased
,What is the effect on gastric emptying when the strength of the
peristaltic contractions of the caudad stomach is increased?
Correct Answer - the rate is increased
What is the effect of the parasympathetic vs sympathetic nervous
system on the peristaltic contractions of the orad stomach?
Correct Answer - parasympathetic: increase contractinos/gastric
emptying
sympathetic: decrease contractions/gastric emptying
What is the effect of the presence of acidic chyme in the duodenum
on gastric emptying? How? Correct Answer - it decreases the
rate of gastric emptying by releasing secretin
What is the effect of fat digestion in the duodenum on the rate of
gastric emptying? How? Correct Answer - it decreases gastric
emptying by secreting CCK
What is the effect of hypertonic chyme in the duodenum on the rate
of gastric emptying? Correct Answer - it decreases it
What is the effect of secretin on gastric emptying? Correct Answer
- it decreases it
What is the effect of CCK on the rate of gastric emptying? Correct
Answer - it decreases it
Via which mechanism does distention of the duodenum and
hypertonic chyme cause a decrease in gastric emptying? Correct
Answer - inhibitory enteric nerves in a short reflex
Which three cells in the gastric mucosa modulate HCl secretion?
Correct Answer - G cells, D cells, and ECL cells
, What do the G cells in the stomach do? Correct Answer - they
secrete gastrin
What doe the D cells in the gastric mucosa secrete? Correct
Answer - somatostatin
What do the ECL cells in the gastric mucosa secrete? Correct
Answer - histamine
Which cells in the stomach secrete HCl? Correct Answer -
parietal cells
In the secretion of HCl by the stomach, what causes H+ to move from
the parietal cell into the stomach lumen? Correct Answer - it is
transported out of the cell through an H-K ATPase that allows K+ to
enter the cell as H+ leaves
What process within the gastric parietal cell forms a proton that will
eventually be pumped into the lumen to form HCl? Correct
Answer - carbonic anhydrase forms H2CO2, which then breaks
down into the H+ and bicarbonate ions
What is the function of bicarbonate in HCl secretion in the stomach?
Correct Answer - the bicarbonate is exchanged into the tissue for
the influx of a Cl ion and enters venous blood
What is the function of Cl in HCl secretion in the stomach? Correct
Answer - as bicarbonate is pumped out of the parietal cell, Cl
enters, traverses the cell, and exits into the stomach lumen via a
channel on the opposite side
What is the rate limiting step in the secretion of HCl by parietal
cells? Correct Answer - the availability of ATP that powers the
H-K ATPase that pumps H+ into the stomach lumen
