Final answer:
Peristalsis is the rhythmic, involuntary contractions of smooth muscles in the alimentary canal that help mix and propel ingestions towards the rectum.
Step-by-step explanation:
The rhythmic involuntary smooth muscle contractions of the alimentary canal that mix and propel ingestions towards the rectum is called peristalsis. This is a continuous sequence of muscle contractions and relaxations that moves in a wave-like fashion to propel food through the gastrointestinal tract. The entire alimentary canal has layers of muscle tissue which, when they contract sequentially, create a squeezing motion that pushes food from the esophagus to the anus.
There are several types of movements involved in the mechanical digestion in different sections of the alimentary canal, including segmental contractions, migrating motility complexes in the small intestine, and mass movements in the large intestine. However, the unifying feature of these movements is the process of peristalsis, which is critical for effective digestion and ensuring that food is pushed along the digestive tract.