BIOM1060 Lecture 6: GIT - Digestion (BIOM1061)
Document Summary
Autonomic (involuntary): passage of food through gut, conversion to chyme and faeces. Nervous system of the git (aka: the gut brain) Digestive activity provoked by mechanical and chemical stimuli (respond to stretch, changes in osmolarity and ph, and presence of substrate or end products of digestion) Effectors of digestive activity are smooth muscle and glands (upon stimulation, receptors initiate reflexes that stimulate smooth muscle to mix and move lumen contents) Neurons (intrinsic and extrinsic) and hormones control digestive activity. Short reflexes: mediated by enteric nerve plexuses (respond to stimuli in git) Long reflexes: respond to stimuli in and outside gut (eg. from autonomic nervous system) Enteric neurons make up bulk of two interconnecting intrinsic nerve plexuses: submucosal nerve plexus: regulates glands and smooth muscle in mucosa, myenteric nerve plexus: controls git motility. Parasympathetic system enhances digestion, sympathetic system inhibits it. Ingestion and sensory analysis of material before swallowing. Mastication: mechanical processing (by teeth, tongue and palatal surfaces)
