Digestion

Chapter 19DigestionWhat is digestion?Process by which the body breaks down food into small nutrient molecules.Can be done mechanically or chemicallyJobs of the Digestive SystemBreaks down food into molecules the body can useAbsorbs broken down molecules into the blood to be carried throughout the bodyEliminates wastesMajor OrgansMouthEsophagusStomachSmall intestineLiverGall bladderPancreasLarge intestineRectum/anusTypes of DigestionMechanicalChemicalPhysically breaks down food into smaller piecesEx: chewing, peristalsisChemicals in the body break foods into smaller chemical building blocks.Ex: Enzyme in saliva breaks starch into sugar- The Digestive Process BeginsThe shape of an enzyme molecule is specific to the shape of the food molecule it breaks down. Here an enzyme breaks down a starch into sugars.

Enzymes6MouthTeeth chew food into small piecesSaliva mixes with food to moisten it; starch breaks down into sugar

EsophagusTube that connects mouth to stomachMixes food with mucus and moves it into the stomach by peristalsis Epiglottis is a flap that blocks food from going down windpipe.

StomachJ-shaped pouchMixes food with digestive juices such as enzymes and acids to turn food into liquid form.

Small intestineMixes liquid from the stomach with enzymes and secretions from the liver and pancreas.Lined with villi to absorb nutrients from the digested food 20-25 ft long!

Liver and GallbladderLargest organ inside of bodyProduces bile to break up fatsBile is stored by the gallbladder

PancreasTriangular organ in between stomach and small intestineProduces insulin and enzymes to break down starches, proteins, and fats

Large intestineContains helpful bacteria to help feed on digested foodWater is removed from waste and absorbed into bloodReadies waste for elimination from bodyOnly 5 ft long but wider than small intestine

Rectum and AnusRectum-compresses food into solid formAnus- muscular opening that removes waste from the body