<P> In much of a digestive tract such as the human gastrointestinal tract , smooth muscle tissue contracts in sequence to produce a peristaltic wave , which propels a ball of food ( called a bolus while in the esophagus and upper gastrointestinal tract and chyme in the stomach ) along the tract . Peristaltic movement comprises relaxation of circular smooth muscles , then their contraction behind the chewed material to keep it from moving backward , then longitudinal contraction to push it forward . </P>
<P> In much of a digestive tract such as the human gastrointestinal tract , smooth muscle tissue contracts in sequence to produce a peristaltic wave , which propels a ball of food ( called a bolus while in the esophagus and upper gastrointestinal tract and chyme in the stomach ) along the tract . Peristaltic movement comprises relaxation of circular smooth muscles , then their contraction behind the chewed material to keep it from moving backward , then longitudinal contraction to push it forward . </P>
where is peristalsis found in the digestive system
where is peristalsis found in the digestive system
much of a digestive tract
much of a digestive tract