Gut Motility

Gut Motility

Peristalsis is a radially symmetrical contraction and relaxation of muscles which propagates in a wave down a muscular tube, in an anterograde fashion. In humans, peristalsis is found in the contraction of smooth muscles to propel contents through the digestive tract. It is wave contraction of longitudinal and circular muscles preceded by wave relaxation of these muscles. Earthworms use a similar mechanism to drive their locomotion. The word is derived from New Latin and comes from the Greek peristallein, "to wrap around," from peri-, "around" + stallein, "to place".

In much of the gastrointestinal tract, smooth muscles contract in sequence to produce a peristaltic wave which forces a ball of food (called a bolus while in the esophagus and gastrointestinal tract and chyme in the stomach) along the gastrointestinal tract. Peristaltic movement is initiated by circular smooth muscles contracting behind the chewed material to prevent it from moving back into the mouth, followed by a contraction of longitudinal smooth muscles which pushes the digested food forward. Catastalsis is a related intestinal muscle process.