Answer:
Peristalsis, involuntary movements of the longitudinal and circular muscles, primarily in the digestive tract but occasionally in other hollow tubes of the body, that occur in progressive wavelike contractions. Peristaltic waves occur in the esophagus, stomach, and intestines.
Peristalsis is an automatic and important process. It moves: Food through the digestive system. Urine from the kidneys into the bladder.
Peristalsis is a series of wave-like muscle contractions that moves food to different processing stations in the digestive tract. The process of peristalsis begins in the esophagus when a bolus of food is swallowed.
When certain muscles in the digestive and urinary tracts contract, it is called peristalsis. Peristalsis is a particular, wave-like kind of muscle contraction because its purpose is to move solids or liquids along within the tube-like structures of the digestive and urinary tracts.
Thanks to Brittanica!
Hope this helped.
-RosemaryAndStars