What is the function of the muscularis layer?

The muscularis layer, typically composed of smooth muscle, is primarily responsible for the movement of food through the digestive tract via peristalsis, which is the coordinated contraction and relaxation of muscle fibers. It generally consists of two layers: an inner circular layer and an outer longitudinal layer, facilitating both segmentation and propulsion of content. Additionally, this layer plays a role in regulating the movement of substances within various organs, contributing to processes such as swallowing, food digestion, and the passage of waste.