The innervation of the intestinal blood vessels is from
|A||The intrinsic enteric nervous system|
|B||The extrinsic sympathetic nervous system|
The extrinsic sympathetic fibres :
These secrete norepinephrine and cause vasoconstriction.
The intrinsic enteric nervous system fibres :
These secrete many different substances. For example, many of them secrete VIP and NO; these cause the hyperemia that occurs during digestion of food.