Maximum postprandial motility is seen in
**Core Concept**
The question is testing the understanding of the physiological response of the gastrointestinal (GI) tract to food intake, specifically the postprandial motility. Postprandial motility refers to the increased movement of the GI tract after a meal, which helps in the mixing and propulsion of food towards the small intestine for absorption.
**Why the Correct Answer is Right**
The correct answer is related to the hormone gastrin, which is released in response to food intake. Gastrin stimulates the contraction of the smooth muscle in the stomach and small intestine, leading to increased motility. This is a part of the enteric nervous system's response to food, mediated by the release of various hormones and neurotransmitters. The hormone gastrin is released by G cells in the stomach and stimulates the release of gastric acid and pepsin, which break down food proteins.
**Why Each Wrong Option is Incorrect**
**Option A:** This is a distractor, as the hormone gastrin is not primarily responsible for the motility of the large intestine.
**Option B:** This is incorrect, as the hormone cholecystokinin (CCK) is primarily involved in the stimulation of the release of bile and pancreatic enzymes, rather than motility.
**Option C:** This option is incorrect, as the hormone secretin is involved in the stimulation of the release of bicarbonate from the pancreas, rather than motility.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that the postprandial motility is a coordinated response of the enteric nervous system, involving the release of various hormones and neurotransmitters.
**Correct Answer: C. Gastrin**