2Digestive System Mechanical digestion Food chewed and mixed in mouth. I. Digestion – the process that breaks food into small molecules so they can be absorbed or taken into body cells.Mechanical digestionFood chewed and mixed in mouth.Food churned in stomach.Food acted on by bile.
3Digestive System B. Chemical digestions Breaks down large molecules to smaller.In mouth , stomach, smallintestines3. EnzymesProteins vital for chemical digestionEnters a reaction and helps to join or break up into substancesAre not changed themselvesCan speed up reactions
4Digestive System Mechanical digestion by tongue and teeth II. Digestion in mouthDiagram of the mouthMechanical digestion by tongue and teethChemical digestionSalivaProduced by the 3 sets of salivary glandsMostly water, but also contains mucus and enzymes (amylase)Amylase starts breakdown of starch to sugar.
5Digestive System Muscular tube 25 cm. long No digestion C. EsophagusEsophagus DiagramMuscular tube25 cm. longNo digestionPeristalsis- waves of contractions that move foodTakes about 4 to 8 secondsPeristalsis found throughout digestive systems
6Digestive System A muscular bag with folds on the inside III. Digestion in the StomachDiagram of the stomachA muscular bag with folds on the insideMechanical digestion done by walls of stomach and peristalsis.Real view
7Digestive System C. Chemical digestion Inside the stomach Hydrochloric acidEnzymes work on proteinMucusLubricates food, making it slickProtects stomach lining from strong digestive juicesD. Food in stomach about 4 hoursE. Food changed to chyme - thin , watery liquid
8Digestive System Small in diameter, but about 6-7 M long IV. Digestion in the small intestineSmall intestines DiagramSmall in diameter, but about 6-7 M long- first part of the duodenum small intestineMajor part of all digestionReceive digestive juices from outside the digestive tractBileFrom the liverGreenish color
9Digestive System Diagram of gallbladder Small intestines continueDiagram of gallbladder3. Store in small sac : the gall bladder4. Breaks fat molecules into smaller pieces(like detergent acts on grease)b. PancreasProduces insulin - helps body use sugar and other carbohydratesProduces enzymes that break down carbohydrates, fats, proteins still further
10Digestive System Many ridges and folds Folds covered with villi C. Walls of small intestineMany ridges and foldsFolds covered with villiTiny, finger like projectionsMake surface area larger so there are more places for to be absorbed.
11Digestive SystemD. Chyme is now a soup of Molecules ready to be absorbed through cells on surface of villi.Capillaries around the villusMolecules of nutrients pass by diffusion and osmosis or by active transport into blood vessels of each villus.Remaining materials are moved into large intestines by peristalsis.
13Digestive System Main job: absorb water from the thin mixture (chyme) V. Absorption in large intestineLarge intestinesMain job: absorb water from the thin mixture (chyme)Homeostasis is maintained.Peristalsis slows down some.Chyme may stay in large intestine for 3 daysWater and sodium are absorbed.
14Digestive System Undigested cellulose Bacteria D. Remaining materialsUndigested celluloseBacteriaFeed on undigested matterProduce vitamins.This is an example of a symbiotic relationship.
15Digestive System Controlled by muscles in the rectum and anus. E. Release of solidified wastesControlled by muscles in the rectum and anus.Release in the form of feces.
16Digestive SystemRememberColon:Food is processed in your digestive system for the purpose of supplying your body with raw materials for metabolism. These raw materials are in the form of nutrients.