The<unk>  <unk>  or intrinsic nervous system is one of the main divisions of the autonomic nervous system (ANS) and consists of a mesh-like system of neurons that governs the function of the gastrointestinal tract. It is capable of acting independently of the sympathetic and parasympathetic nervous systems, although it may be influenced by them. The<unk>  is nicknamed the "second brain". It is derived from neural crest cells. The<unk>  is capable of operating independently of the brain and spinal cord, but does rely on innervation from the autonomic nervous system via the vagus nerve and prevertebral ganglia in healthy subjects. However, studies have shown that the system is operable with a severed vagus nerve. The neurons of the<unk>  control the motor functions of the system, in addition to the secretion of gastrointestinal enzymes. These neurons communicate through many neurotransmitters similar to the CNS, including acetylcholine, dopamine, and serotonin. The large presence of serotonin and dopamine in the gut are key areas of research for neurogastroenterologists.
Enteric nervous system
Peripheral nervous system
Central nervous system
Nervous system
Cranial nerves
Reproductive system
Urinary system
Gastrointestinal tract