Final answer:
The ENS, a key part of the PNS, controls digestive functions by directly managing the gastrointestinal tract's muscles and glands, and can operate without CNS input. The autonomic nervous system can modulate ENS activity, affecting digestion through sympathetic or parasympathetic stimulation.
Step-by-step explanation:
The Peripheral Nervous System (PNS), specifically the enteric nervous system (ENS), plays a crucial role in the regulation of digestive functions. The ENS, a part of the PNS that operates independently of the Central Nervous System (CNS), directly controls the smooth muscle and glandular tissue in the gastrointestinal tract. It is considered a component of the autonomic nervous system that influences digestion.
Through mechanisms such as reflexes initiated by stretch receptors in the stomach, the ENS can activate smooth muscle fibers to increase motility and aid in digestion without requiring CNS intervention. On the other hand, the autonomic nervous system, when activated by stress (sympathetic response) or rest (parasympathetic response), can modulate the activity of the ENS, either inhibiting or stimulating gastrointestinal secretion and motility, respectively.