Final answer:
Food movement through the gastrointestinal tract is facilitated by peristalsis, which involves sequential, wave-like muscle contractions of both circular and longitudinal muscles in the tract's walls, functioning involuntarily.
Step-by-step explanation:
The process by which food movement takes place within a person's gastrointestinal tract is known as peristalsis involving the circular and longitudinal muscles. During peristalsis, alternating waves of muscle contraction and relaxation propel food through the digestive system. This process involves layers of smooth muscle tissue in the walls of the gastrointestinal tract which contract sequentially, ensuring that food is pushed in one direction—from the mouth to the anus. The contractions act like rings, systematically tightening and relaxing to move the food and mix it with digestive juices. Importantly, peristalsis is an involuntary process, meaning it occurs without conscious control.