Parasympathetic nerve fiber (colon)

Parasympathetic nerves in the colon are extrinsic autonomic nerve fibers, primarily derived from the pelvic splanchnic nerves (S2–S4), that innervate the distal colon and rectum. They facilitate colonic peristalsis, secretomotor activity, and defecation via stimulation of enteric neural circuits. These fibers are not a molecular entity but a functional/anatomical component of the nervous system. Their neurotransmitter is mainly acetylcholine, acting on muscarinic receptors in the enteric nervous system. Dysfunction or damage to these nerves can lead to disorders of colonic motility and defecation.

Other names

Parasympathetic innervation of the colonSacral parasympathetic nerves (colon)Pelvic splanchnic nerve fibers (colon)

Modulation of neurotransmitter release (primarily acetylcholine) at neuroeffector junctions in the colon Enhancement or inhibition of parasympathetic activity via central or ganglionic mechanisms