Gastroenterology MCQ Answer 32

Answer: a, d

The migrating motor complex (MMC) is a cyclic pattern of spike bursts and muscular contractions that migrate from the duodenum to the terminal ileum. The MMC is divided into four phases: phase I-the period of quiescence with no activity; phase II-accelerating irregular spike activity; phase III-the activity front with a series of high-amplitude, rapid spikes corresponding to strong, rhythmic gut contractions; and phase IV-subsiding activity. In humans the cycle lasts about 90 to 120 minutes. Each phase passes in sequence along the bowel, and when the terminal ileum is reached, the process resumes in the proximal gut. This interdigestive cycle is interrupted and replaced by rapid spiking activity (similar to phase II) when the gut receives a food bolus. The duration of the interruption depends on the volume and nature of the food stuffs with fats causing the largest duration of rapid spiking. Blood levels of the GI hormone, motilin, correlate closely with MMC activity and exogenous motilin can induce the MMC front. Other hormones whose serum levels parallel MMC activity are pancreatic polypeptide and somatostatin. Drugs that can initiate the MMC front include histamine, metoclopramide, and morphine.

Category: Gastroenterology MCQs