Which process moves food and waste through the gastrointestinal system?

Which process moves food and waste through the gastrointestinal system?

• A. Peristalsis
• B. Segmentation
• C. Absorption
• D. Micturition

Answer: (A)

Propulsion of contents along the GI tract is produced by peristalsis. This involves coordinated wave-like contractions of smooth muscle that push food forward: the circular muscles behind the bolus contract to close off the path while the longitudinal muscles ahead shorten the segment, creating a forward wave that moves the material from esophagus through the intestines. Segmentation, by contrast, mainly mixes chyme and increases contact with digestive enzymes rather than moving it forward. Absorption is the uptake of nutrients across the intestinal lining, not a movement process. Micturition is urination, unrelated to the gastrointestinal tract.

Propulsion of contents along the GI tract is produced by peristalsis. This involves coordinated wave-like contractions of smooth muscle that push food forward: the circular muscles behind the bolus contract to close off the path while the longitudinal muscles ahead shorten the segment, creating a forward wave that moves the material from esophagus through the intestines. Segmentation, by contrast, mainly mixes chyme and increases contact with digestive enzymes rather than moving it forward. Absorption is the uptake of nutrients across the intestinal lining, not a movement process. Micturition is urination, unrelated to the gastrointestinal tract.