In: Anatomy and Physiology
Autonomic system is the extrinsic system of nerves supplying the gut. It consists of parasympathetic and sympathetic innervation.
Parasympathetic innervation: it is made up of cranial and secral divisions:-
Cranial parasympathetic fibres originate in medula, come through Vagus and supply the esophagus, stomach, small intestine, pancreas and first half of large intestine. They also make synaptic connections with intramural plexus.
Sacral parasympathetic fibres originate in sacral spinal cord, pass through pelvic nerves to hypogastric ganglion as a post ganglionic fibre, supply the distal half of large intestine and rectum. The sigmoid, rectal and anal regions have an especially rich supply of parasympathetic fibres which help in defecation reflex. Functions:-
Sympathetic innervation:- the sympathetic fibres to gut arise from T8 to L2. The sympathetic innervate all portions of GITrather than being more extensively supplied to portions near the oral cavity and anus. Functions:-
Enteric Nervous System consists of two plexus-