Final answer:
The GI tube tissue layer responsible for segmentation and peristalsis is the muscularis externa, which contains inner circular and outer longitudinal smooth muscle layers.
Step-by-step explanation:
The GI tube tissue layer responsible for the actions of segmentation and peristalsis is the muscularis externa. This layer is comprised of two types of smooth muscle: the inner circular muscle and the outer longitudinal muscle. The coordinated contractions of these muscles are essential for mechanically breaking down food.
mixing it with digestive juices, and propelling food through the GI tract. During peristalsis, rhythmic contractions of these muscles push the food along the GI tract, while during segmentation, the contractions mix the food with digestive secretions and increase the interaction with the mucosal surface for absorption.