What is the primary mechanism used to propel chyme along the small intestine?

The primary mechanism used to propel chyme along the small intestine is peristaltic movements. Peristalsis is a coordinated, wave-like contraction of the smooth muscle lining the gastrointestinal tract. This allows the chyme, which is partially digested food mixed with digestive juices, to move in a rhythmic manner from the duodenum to the ileum of the small intestine.

Peristaltic movements serve to efficiently push the chyme along, regulating its passage while mixing it with digestive enzymes and bile, which are important for nutrient absorption. This movement is vital for the digestion process, ensuring that nutrients are exposed to the absorptive surfaces of the intestinal lining.

While segmentation does occur in the small intestine and is important for mixing and enhancing absorption, its main function is not propulsion but rather to break down the chyme into smaller pieces and increase contact with the intestinal walls. Consequently, segmentation complements peristalsis, but does not primarily serve to propel chyme down the intestinal tract as effectively as peristaltic movements do.