Gastrointestinal regulation

Autonomic nervous system

enteric nervous system

GI hormones

not regulated by homeostasis

its function is to maximise digestion and absorb nutrients

enteric nervous system

• divided between submucosal plexis and myenteric plexus

• controls GI function through short and long reflex arcs

• does not require external inputs

• sensory receptors detect environment and initiate relfex arcs

chemoreceptors stimulus relay message to central nervous system—> autonomic —> enteric —>effector cells and endocrine cells

endocrine pathways

• secrete hormone in response to specific stimuli

• hormones interact with target cells and causes a response that changes conditions inside GI tract

• secretion controlled by enteric nervous system

cephalic phase

• controls stomachs secretion of gastric juices and stomach motility

gastric phase

• initiated by bolus reaching the stomach

• distends stomach and activates stretch receptors

• change in proteins conc- detected by chemoreceptors (monitors different substance in GI tract)

• induces peristalsis

• stimulates secretion of gastric juices and gastrin

intestinal phase

• initiated by chyme entering small intestine

• activates chemoreceptors in the duodenum activating long and short reflex arcs

• inhibits gastric juice secretion

• reduces motility of stomach

• stimulates secretion of bile and pancreatic juices