Retropulsion is the event seen in:
High-Yield Explanation
Retropulsion is the event seen at the pylorus. As the pyloric wall contracts, some amount of food (chyme) moves into the duodenum whereas the remaining food rebounds from the pyloric sphincter. This is retropulsion. It will again move forward. This back and foh movement allows a thorough mixing of foodstuffs with the gastric juice, helping formation of chyme.