The most important factor for regulating secretions in the small intestine is
A) presence of bicarbonate ions
B) stimulation by secretin
C) stimulation by cholecystokinin
D) presence of chyme
E) the acidity of the chyme

Question

Quizplus · Accepted Answer

The presence of chyme is the most important factor for regulating secretions in the small intestine because it triggers the release of secretin and cholecystokinin from the duodenal mucosa. These hormones stimulate the secretion of bile from the liver and pancreatic enzymes and bicarbonate ions from the pancreas, respectively, to aid in digestion and neutralize the acidic chyme. The presence of bicarbonate ions and the acidity of the chyme are also important factors, but they are secondary to the presence of chyme itself.

The Most Important Factor for Regulating Secretions in the Small