peristalsis
The organs of the digestive system are lined with muscles. The muscles contract, or tighten, to push food through the system Figure below . The muscles contract in waves. The waves pass through the digestive system like waves through a slinky. This movement of muscle contractions is called peristalsis . Without peristalsis, food would not be able to move through the digestive system. Peristalsis is an involuntary process, which means that it occurs without your conscious control.