Migrating Motor Complex (MMC) and Vomiting

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Migrating Motor Complex (MMC) and Vomiting

• Dr. Alzoghaibi

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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

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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

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Migrating Motor complex (MMC)

• Characteristics functions (cont)
• - takes 80-120 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

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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

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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

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Peptic Ulcer and Vomiting
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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

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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

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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

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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

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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)