Final answer:
Dual innervation is the control of viscera by both sympathetic and parasympathetic nervous system fibers, affecting processes like GI motility and secretions. The enteric system also plays a role in gut function with two plexuses regulating various aspects of digestion.
Step-by-step explanation:
Dual innervation refers to the control of visceral organs by both sympathetic and parasympathetic fibers. These two aspects of the autonomic nervous system frequently have opposing effects on the target organs, such as the alimentary canal, which includes smooth muscle, and exocrine and endocrine glands. The sympathetic nervous system is often associated with the fight-or-flight response, leading to a decrease in gastrointestinal (GI) secretion and motility, while the parasympathetic nervous system is connected with the rest-and-digest response, increasing GI secretion and motility.
The enteric nervous system also provides intrinsic innervation of the alimentary canal, running from the esophagus to the anus and featuring two major plexuses: the myenteric plexus, which controls the rhythm and force of muscular contractions, and the submucosal plexus, which regulates digestive secretions and responds to the presence of food.