Basic GI Regulation
- The alimentary tract is controlled through a combination of both nervous and endocrine regulatory mechanisms. Nervous control is mediated by an extensive neuronal network within the GI system which can coordinate GI actions completely locally but also receives significant modulatory input from the central nervous system. Endocrine control is mediated by a variety of GI peptide hormones that are secreted by specialized cells in one segment of the GI Tract and which control the actions of a different segment of the alimentary tract.
- Enteric Nervous System:
- The Enteric Nervous System refers to the enormous number of neurons which exist within the GI tract that contribute to controlling nearly all GI functions. Functional control by the enteric nervous system continues even if connections with the CNS are severed.
- Autonomic GI Neural Control:
- Although the enteric nervous system can act independently, it receives significant efferent input from the Autonomic Nervous System (ANS). Additionally, the enteric nervous system sends significant afferent input to the CNS, thus informing the brain of alimentary tract status.
- GI endocrine hormones are secreted by cells in one GI segment and affect functions of other GI segments. Importantly, all GI endocrine hormones are peptide hormones.
- GI Hormones