Peristalsis is a sequence of wave-like muscle contraction involved in the movement of food and other liquid particles in a digestive tract to different processing organs present in the digestive system.
This process originates from the esophagus when a completely chewed food is swallowed. These involve reflexive movements of the circular and longitudinal muscles majorly in the digestive area but sometimes in hollow tubes that exist in progressive wave-like contractions. Peristalsis waves are present in stomach, esophagus, and intestines. These waves could be shorter, longer, continuous or continual that move within the entire length of the organs based on their location.
Peristaltic waves in esophagus start from the upper position of the tube and pass into the complete length and impel the food into the stomach. This could be termed as Esophageal Peristalsis. The food particles left behind the esophagus begins with the secondary peristaltic waves that eliminate leftover particles. A single wave moves along the complete length of the tube. In cud-chewing animals like cattle, sheep, giraffes, and camels the reverse peristalsis happens such that the food is brought again to the mouth for chewing.
The peristaltic waves get disappeared after the stomach gets filled. The excess fats present in the food particles stop these movements until it gets diluted with gastric juices. These waves help in mixing the stomach content and drive the food into the small intestine. Normally, two to three waves exist at once in separate areas of the stomach.
The stimulation of smooth muscle tissues for the existence of food particles in the small intestine is responsible for contractions that travel from the restorative point in both directions is termed as Intestinal Peristalsis.
Usually, they are found in the small intestine and move in varying distances. These expose food to the intestinal wall for immersion and keep moving forward.
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