THORAX ABDOMEN AND PELVIS

Detailed explanation-1: -The muscularis externa is responsible for segmental contractions and peristaltic movement in the GI tract. These muscles cause food to move and churn together with digestive enzymes down the GI tract. The muscularis externa consists of an inner circular layer and a longitudinal outer muscular layer.

Detailed explanation-2: -Peristalsis squeezes your esophageal muscles from top to bottom. This pushes food and liquid along. If you could see peristalsis, it would look like a wave passing down your esophagus. To keep food and liquids moving in the right direction, your digestive tract has special muscles along its course called sphincters.