Migrating motor complex is due to which GI hormone-
**Core Concept**
The migrating motor complex (MMC) is a pattern of gastrointestinal (GI) contractions that occurs during periods of fasting, playing a crucial role in maintaining GI health and preventing bacterial overgrowth. The MMC is generated by the interplay between various GI hormones and the enteric nervous system.
**Why the Correct Answer is Right**
The MMC is primarily regulated by the hormone **motilin**, which is released from the duodenum and stimulates the contraction of the GI tract. Motilin acts on the muscarinic receptors, increasing the release of acetylcholine, which in turn stimulates the smooth muscle contractions. This process helps to clear the GI tract of residual food, bacteria, and other debris, thereby maintaining a healthy GI environment.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because **gastrin** is primarily involved in stimulating gastric acid secretion and not directly involved in the generation of the MMC.
**Option B:** This option is incorrect because **secretin** is primarily involved in stimulating pancreatic bicarbonate secretion and not directly involved in the generation of the MMC.
**Option C:** This option is incorrect because **cholecystokinin (CCK)** is primarily involved in stimulating gallbladder contraction and pancreatic enzyme secretion, and not directly involved in the generation of the MMC.
**Clinical Pearl / High-Yield Fact**
Remember that the MMC is a critical mechanism for maintaining GI health, and alterations in motilin or other GI hormones can lead to conditions such as gastroparesis or small bowel bacterial overgrowth.
**Correct Answer: C. Motilin**