Digestive System Flashcards
What are 3 examples of accessory organs?
Liver, Gall bladder, pancreas, salivary glands, teeth
What is peristalsis?
involuntary, contraction/relaxation of smooth muscles to move down GI tract
Where does majority of the absorption of nutrients occurs?
Small intestine
How is the volume/composition of the contents of the lumen regulated? (2)
Mechanoreceptors – stretch of GI tract wall
Osmoreceptors/chemoreceptors - compositions of contents of lumen
Is the sympathetic NS inhibitory or excitatory to the digestive system?
Inhibitory
Describe the difference between the short and long reflex of the enteric NS
Short reflex – stimulus is sent from GI tract to sensory receptors to enteric nervous system to produce response (all within wall of GI tract)
Long reflex – stimulus is sent from GI tract to brain, autonomic nervous system produces response in GI tract (from lumen to CNS and back, eg. Sight/taste of food)
What is the role of the liver?
Produces bile (bile salts) necessary for emulsification and absorption of lipids.
What is the role of the gall bladder?
Stores, concentrates, and delivers bile into duodenum via common bile duct.
What are the 3 mechanism that increase the surface area of SI?
Circular folds – small length, more surface area (corrugated iron)
Villi – fingerlike projections of mucosa, on circular folds
Microvilli - “brush border” on top of villi
What enzymes reside in the mouth?
Salivary amylase
What enzymes reside in the stomach?
HCl and Pepsin
What enzyme hydrolysed lipids?
Lipase
What are emulsifying agents?
Molecules with a polar and non-polar side (eg. Phospholipid)
What is the cephalic phase?
function of GI system being influenced by the brain
What is the difference between anabolic/catabolic?
Anabolism - “to build up”
Catabolism - “to break down”
