where do both peristalsis and segmentation occur?
GI Motitility In the Stomach. 1  Two types of movement (motility) occur in the stomach: peristalsis and segmentation (mixing). 2  The contractions occur about every 20 seconds and proceed from the body of the stomach toward the pyloric sphincter. 3  About 20% of the contractions in the stomach are peristaltic waves.