A 45-year-old man consumes a meal consisting of 20% fat, 50% carbohydrate, and 30% protein. The following gastrointestinal hormones are released at various times over the next 6 hours: gastrin, secretin, motilin, glucose-dependent insulinotropic peptide, and cholecystokinin. Which of the following structures is most likely to release all five hormones in this man?

Question

Quizplus · Accepted Answer

The hormones listed are released in response to different nutrients and signals in the digestive process. Gastrin is released by G cells in the antrum of the stomach in response to stomach distension and presence of protein. Motilin is released by cells in the duodenum in response to fasting and stimulates migrating motor complexes. Secretin is also released by cells in the duodenum in response to acidic chyme and regulates bicarbonate secretion from the pancreas. Glucose-dependent insulinotropic peptide (GIP) is released by cells in the duodenum and jejunum in response to fatty acids and carbohydrates, stimulating insulin release from the pancreas. Cholecystokinin (CCK) is released by cells in the duodenum and jejunum in response to fatty acids and amino acids, stimulating gallbladder contraction and pancreatic enzyme secretion. Therefore, the duodenum is the most likely structure to release all five hormones in response to the specific macronutrient composition of this meal.

A 45-Year-Old Man Consumes a Meal Consisting of 20% Fat