Peristaltic contractions of the esophageal muscle push the food down the esophagus. Pulsation is an important side effect of the peristaltic pump. Tubing are also used in peristaltic pump applications. However, peristaltic pumps can be designed to approach these ideal peristaltic pump parameters. Large-volume pumps usually use some form of peristaltic pump. Wave-like peristaltic contractions move the food through the stomach for digestion. This is commonly referred to as a roller pump, or peristaltic pump. The dilation is often accompanied by a paralysis of the peristaltic movements of the bowel. The flow rate of a peristaltic pump is in most cases not linear. These can be based on peristaltic or a venturi type of pump. Normal peristaltic movement of the esophagus is not seen. Such an ideal peristaltic pump can not be constructed in reality. Bowel sound may be increased (borborygmi) due to excessive peristaltic action of the stomach. Modern refractometers have the option of a built-in peristaltic pump. During deglutition, they contract and cause peristaltic movement in the pharynx.