The enteric system is composed of local sensory neurons that detect changes in the tension of the gut walls and the chemical environment. The plexuses are located between the various layers of muscle and endothelium. The myenteric plexus and the submucous plexus are the two major plexuses. While the enteric system can function independently, Sympathetic and parasympathetic input provides an additional level of control. Parasympathetic preganglionic neurons project directly to enteric ganglia of the stomach, colon, and rectum.
Sympathetic innervation is primarily postganglionic from prevetebral sympathetic ganglia.
These ganglia project directly to enteric plexus in the wall of the stomach, small intestine, and the colon. 4.The Hypothalamus and the Nucleus of the Solitary tract Play a Major Role in Controlling the Output of the Autonomic Nervous System 4 . The autonomic nervous system is influenced by many regions of the brain and this influence is mediated by the hypothalamus. First fibers in the hypothalamus project to nuclei in the brain stem and the spinal cord that act on preganglionic autonomic neurons to control temperature, heart rate, blood pressure etc. Secondly, the hypothalamus acts on the endocrine system to release hormones that influence autonomic function.