1. Migrating Motor Complex (MMC) and Vomiting
Dr. Alzoghaibi

2. Migrating Motor complex (MMC)
Digestive state:
When nutrients are present and digestive process are ongoing
Interdigestive state
When the digestion and absorption of nutrients are complete, 2-3 hrs after a meal

3. Migrating Motor complex (MMC)
Characteristics & functions:
Pattern of motility in the interdigestive state
- bursts of electrical & contractile activities are separated by longer quiescent periods
- pattern of motility in fasting, conscious & sleep stages
- begins at distal stomach to ileum
- antral contraction to propel the remaining materials bigger than 7mm

5. Migrating Motor complex (MMC)
Characteristics & functions (cont):
- takes min for one activity front (from antrum to ileum)
- 3-6 cm/min in duodenum
- 1-2 cm/min in ileum
MMC organizer
- ENS
- CCK & gastrin MMC
- motilin MMC

6. Migrating Motor complex (MMC)
Cycling of the MMC continues until it is ended by the ingestion of food
Termination requires the physical presence of a meal in the upper digestive tract
Vagal efferent signals to ENS interrupt the MMC and initiate mixing motility during ingestion of a meal
After vagus nerves are cut, a large quantity of ingested food is necessary to interrupt the interdigestive motor pattern (MMC), and the interruption is often incomplete
Intravenous feeding does not end the fasting pattern

7. Migrating Motor complex (MMC)
Adaptive significance of MMC
Gallbladder contraction and delivery of bile to the duodenum is coordinated with the onset of MMC in the intraduodenal region
Appears also to be a mechanism for cleaning indigestible debris
Plays a housekeeper role in preventing the overgrowth of microorganisms that might occur in the small intestine

8. Peptic Ulcer and Vomiting

9. Peptic Ulcer Specific causes of peptic ulcer:
Bacterial infection by Helicobacter Pylori
Increased secretion of acid-peptic juices
Smoking, because of increased nervous stimulation
Alcohol, because it tends to break down the mucosal barrier
Aspirin, which also has a strong propensity to break down this barrier

10. Peptic Ulcer General features: Reduced mucosal defense & acid amounts
# of parietal cells
sensitivity to gastrin
stomach emptying
inhibition of gastrin release by acid
rate of duodenal HCO3- secretion
For duodenal ulcer: Pain is felt during fasting and relieved by eating which the opposite to gastric ulcer

11. Helicobacter pylori (H. pylori)
Correlation between H. pylori infection and the incidence of gastric and duodenal ulcer (peptic ulcer)
Remove of bacterial infection reduce ulcer recurrence
Mechanism of H. pylori in the genesis of ulcers:
urea urease ammonia neutralizes acid
(protect bacteria)
Ammonia destroys the protective mucosa
H. pylori gastrin secretion
antibiotic is effective in eradication of H. pylori

12. Vomiting Expulsion of gastric contents Preceded by:
retching, nausea, sweating, dilation of pupil, heartbeat, dizziness
- controlled by vomiting center
- different areas have receptors & input to vomiting center:
-distention of stomach
-tickling back of throat
-injury of genitourinary system

13. Vomiting The events: 1- wave of reverse peristalsis (Retroperistalsis)
2- forced inspiration (abdominal pressure)
3- forceful abdominal muscles
4- relaxed pyloric sphincter, stomach and lower esophageal sphincter (LES)