THORAX ABDOMEN AND PELVIS

Detailed explanation-1: -Peristalsis is a series of wave-like muscle contractions that move food through the digestive tract. It starts in the esophagus where strong wave-like motions of the smooth muscle move balls of swallowed food to the stomach.

Detailed explanation-2: -The smooth muscle portion of the esophagus has myenteric plexus similar to the small intestine. However, peristalsis in the smooth muscle portion of the esophagus is very different than the intestine; the esophagus, but not intestine, can produce peristalsis at will (primary peristalsis).

Detailed explanation-3: -In the esophagus, two types of peristalsis occur: First, there is a primary peristaltic wave, which occurs when the bolus enters the esophagus during swallowing. The primary peristaltic wave forces the bolus down the esophagus and into the stomach in a wave lasting about 8–9 seconds.