PHYS20008 Lecture Notes - Lecture 29: Enteric Nervous System, Parasympathetic Nervous System, Amylase
21 Jul 2019
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Lecture 29: digestion 2: upper gi tract - 16/05/19. Digestive reflexes triggered by stimuli received in the brain eg. sight, sound, smell of food: signals come out of medulla via parasympathetic nervous system. Mechanical digestion (mastication): chewing involves slicing, tearing, grinding and mixing of food by the teeth. Role of gastro-oesophageal sphincter failure of relaxation swallowing difficulties ineffectiveness reflux oesophagitis heartburn separates oesophagus from stomach. Disorders relaxes to allow entry of food. 3 general functions: storage (and control of exit, protection, acid environment destroys bacteria and other pathogens, stomach must also protect itself from autodigestion , digestion, enzymes, acid assists. Not a lot of absorption some absorption of water and alcohol. Peristaltic contractions squeeze chyme against pyloric sphincter food pushed up against and comes back to mix it. Pyloric sphincter regulates how quickly chime moves into duodenum. Volume of chyme in stomach: more -> faster you want to get it out.
