The migrating motor complex in humans-
A. Occurs only in the small intestineB. Requires an intact intrinsic nervous system for coordinated propagation
C. Is the result of food-mediated distension of the small intestine
D. Mixes intestinal contents with bile and the digestive enzymes.
The answer is B.
An intact enteric
nervous system is essential for propagation of migrating motor complexes along
the bowel. During the interdigestive period, the GI tract undergoes regular
increases in peristaltic contractile activity at about every 90 mm that are
termed migrating motor complexes. Originally recorded from the small intestine,
they begin in the smooth muscle of the esophagus or the stomach. They are
commonly associated with periodic increases in the hormone motilin. Although it
is still unclear, they appear to serve a "house keeping function" by
clearing the GI tract of luminal contents. They are immediately interrupted
when a meal is ingested.
