A scientist is studying the mechanism by which the gastrointestinal system coordinates the process of food digestion. Specifically, she is interested in how distension of the lower esophagus by a bolus of food changes responses in the downstream segments of the digestive system. She observes that there is a resulting relaxation and opening of the lower esophageal (cardiac) sphincter after the introduction of a food bolus. She also observes a simultaneous relaxation of the orad stomach during this time. Which of the following substances is most likely involved in the process being observed here?
ANeuropeptide-Y
BSecretin
CGhrelin
DVasoactive intestinal polypeptide
EMotilin
Nine healthy subjects participate in a study of gastric secretions. Subjects are asked to eat a meal at hour 0, at which time the pH of stomach contents and rate of stomach acid secretions are measured over the next 4 hours. Results of the study are shown. Which of the following mediators is most active at point A in the graph?
ASecretin
BAcetylcholine
CProstaglandin
DGlucose-dependent insulinotropic peptide
ESomatostatin
A 49-year-old male complains of heartburn, epigastric pain, and diarrhea. He has a past medical history significant for heartburn that is nonresponsive to omeprazole. He denies any alcohol intake, and has not been taking any nonsteroidal anti-inflammatory drugs. An endoscopy is performed, which shows two ulcers in the proximal duodenum, and one in the distal third of the duodenum. Which of the following is most likely true about this patient’s current condition?
AChronic atrophic gastritis would decrease the suspected hormone level
BSecretin administration would suppress the release of the suspected hormone in this patient
CParietal cell hypertrophy is likely present
DThe suspected hormone acts via a receptor tyrosine kinase signaling pathway
EIncreasing omeprazole dose will likely decrease the suspected hormone level
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