What type of muscle movement does peristalsis involve?

Peristalsis involves alternating contraction and relaxation of the smooth muscles in the walls of the digestive tract. This coordinated movement is essential for propelling food through the esophagus, stomach, and intestines. It works by creating a wave-like motion that pushes the contents forward, facilitating the digestive process and ensuring that food is mixed with digestive juices along the way.

This type of muscle movement is involuntary, meaning it occurs automatically without conscious control, which differentiates it from voluntary muscle movements, like swallowing, which require intentional muscle effort. Other options that focus on muscle spasms or only specific actions fail to encompass the rhythmic and continuous nature of peristalsis, which is crucial for effective digestion. The focus on alternating contraction and relaxation highlights the unique mechanism of peristalsis, emphasizing the importance of this movement in maintaining normal digestive function.