enteric nervous system morphology trait Any measurable or observable characteristic related to the shape, structure, color, or pattern of the part of the autonomic nervous system that innervates the gastrointestinal tract, the pancreas, and the gallbladder and can autonomously sense the tension and the chemical environment in the gut and regulate blood vessel tone, motility, secretions, and fluid transport. Trait.ontology VT:0001044 autonomic nervous system morphology trait