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Large Intestine - Anatomy & Physiology (view source)
Revision as of 13:13, 16 July 2008
, 13:13, 16 July 2008→Innervation
==Innervation==
==Innervation==
*Like the [[Small Intestine - Anatomy & Physiology|small intestine]], the large intestine recieves sympathetic and parasympathetic innervation.
*Similar to the [[Small Intestine - Anatomy & Physiology|small intestine]], there are pacemaker cells that generate an action potential.
*Cells are able to function as a syncytium due to gap junctions, allowing the action potential to spread.
**Contractions are generated in the forward (peristaltic) and backward (antiperistaltic) directions. Antiperistaltic contractions move ingesta into the caecum in some species.
*The formation of action potentials is under a much stronger neural influence than in the [[Forestomach - Anatomy & Physiology|stomach]] and [[Small Intestine - Anatomy & Physiology|small intestine]].
*The large intestine recieves sympathetic and parasympathetic innervation.
*Neurones interact with the myenteric plexus to affect contractility, and with the submucosal plexus to affect secretions.
*Neurones interact with the myenteric plexus to affect contractility, and with the submucosal plexus to affect secretions.
**The '''sympathetic '''have coeliac, cranial mesenteric and caudal mesenteric ganglia.
**The '''sympathetic '''have coeliac, cranial mesenteric and caudal mesenteric ganglia.
**As the sympathetic fibres leave the ganglia, they surround their respective artery.
**As the sympathetic fibres leave the ganglia, they surround their respective artery.
**'''Parasympathetic''' innervation stimulates peristalsis.
*Parasympathetic innervation increases the frequency of action potentials and thus stimulates peristalsis.
*Sympathetic innervation has the opposite effect.
*Motility of the large intestine increases during meals, possibly as a result of gastrin and cholecystokinin secretion.
==Lymphatics==
==Lymphatics==