Answer:
The correct answer is in the walls of the tract organs.
Step-by-step explanation:
The regulation of digestive activities is carried out by intrinsic (systemic) and extrinsic nerves, as well as digestive hormones. And as in the rest of the regulatory systems, sensorial receptors, integration systems and effectors (cells that execute the regulatory response) participate. In vertebrates, this regulatory system overlaps the basic activity of the smooth muscles of the digestive system, modulating it, in addition to exerting other effects.