Final answer:
Peristalsis is the term for the muscular contractions that push food through the esophagus. This coordinated, wave-like action of the smooth muscles ensures the unidirectional movement of the food bolus from the mouth to the stomach.
Step-by-step explanation:
The muscular contractions that push food through the esophagus are called peristalsis. During the esophageal phase of swallowing, a series of coordinated movements involving the circular and longitudinal muscle layers of the esophagus propel the food bolus toward the stomach. Peristalsis involves sequential, alternating waves of contraction and relaxation of the smooth muscles within the walls of the esophagus, ensuring the unidirectional flow of the food bolus from the mouth to the stomach.
The functioning of peristalsis is so efficient that even if a person were standing on their head, the food and liquids would still reach the stomach due to this powerful mechanism. The process is controlled by the medulla oblongata and requires the coordinated action of multiple muscles and the nervous system to function properly.