Final answer:
Smooth muscle tissue in the walls of the digestive system is responsible for the involuntary contractions known as peristalsis, which propels food through the digestive tract.
Step-by-step explanation:
The tissue responsible for contractions during peristalsis in the digestive tract is the smooth muscle tissue. This type of muscle tissue is found in the walls of the digestive system, including the stomach and small intestine, and it enables the involuntary process of peristalsis. Peristalsis is characterized by alternating waves of muscle contraction and relaxation that help to move food through the digestive tract.
Smooth muscle cells are spindle-shaped with a single nucleus and do not show visible striations. These cells are organized into layers within the digestive tract, with the small intestine, for example, featuring an inner circular layer and an outer longitudinal layer. This double-layer structure is well-suited for the peristaltic movements that propel food along the digestive canal.