Physiological Basis of Electrogastroenterography
Motility of GI tract is results from coordinated contractions of smooth muscle, which in turn derive from two basic patterns of electrical activity across the membranes of smooth muscle cells — slow waves and action potentials. Slow waves are initiated by pacemakers — the interstitial cells of Cajal (ICC). Slow wave frequency varies in the different organs of the GI tract and is characteristic for that organ. They set the maximum frequency at which the muscle can contract:
- stomach — about 3 waves in a minute,
- duodenum — about 12 waves in a minute,
- ileum — about 8 waves in a minute,
- rectum — about 17 waves in a minute.
- jejunum — about 11 waves in a minute.
The electrical activity of the GI tract can be subdivided into two categories: electrical control activity (ECA) and electrical response activity (ERA). ECA is characterized by regularly recurring electrical potentials, originating in the gastric pacemaker located in the body of stomach. The slow waves are not a direct reason of peristalsis of a GI tract, but a correlation between deviations of slow waves from norm and motility abnormalities however is proved.
Read more about this topic: Electrogastrogram
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