Question

Peristalsis contributes to the locomotion of many annelids and the movement of food in the digestive tract (see Concept 41.3). Using the muscles of your hand and a toothpaste tube as a model of peristalsis, how would your demonstration differ for the two processes?

Short answer

Scientists restrict the toothpaste tube at various points along its length. Encircle it with the palm and squeeze concentrically for the peristalsis movement. In comparison, peristalsis in worm mobility is demonstrated when leaving the cap on of toothpaste.

Step-by-step solution

Peristalsis in the movement of food

The digestion process begins when food enters the mouth. Digestion aids in the breakdown of food so that the body can use its contents. After entering the mouth, food goes down the esophagus, through the stomach, and into the intestines, where it is pushed forward and eventually exits through the anus.

Peristalsis contributes to the locomotion of many annelids 

Worms move about in a variety of ways. Muscles mainly cause body movement in planarians and other flatworms in the abdominal wall applying localized forces against the interstitial fluid.

Longitudinal muscles tightening around the fluid-filled body cavity of nematodes (roundworms) propel the animal forward in wavelike motions known as undulations.

Many annelids, including earthworms, utilize circular and longitudinal muscles to modify the shape of particular fluid-filled segments divided by septa. Peristalsis, a movement produced by repetitive waves of muscular contractions moving from front to back, is caused by these form alterations.

Using the muscles of the hand and a toothpaste tube as a model of peristalsis

In the model, the peristalsis movement occurs when individuals constrict the toothpaste tube at various points at their length and encircle it with their hand or squeeze concentrically. Whiledemonstrating the flow of food through the digestive tract, remove the cap from the toothpaste tube.

In contrast, when the scientist demonstrates how peristalsis leads to worm mobility, leave the cap on the toothpaste.