2. 1. stages in food processing 1.ingestion 2.digestion 3.absorption 4.elimination 2. digestion - the process that breaks down food into small molecules so that they can be absorbed and moved into the blood 3. mechanical digestion - takes place when food is chewed, mixed, and churned

3. 4. chemical digestion - chemical reactions occur that break down large molecules of food into smaller ones 5. What happens after digestion? -from blood, food molecules transported across cell membrane to be used by the cell - unused molecules leave your body as wastes 6. enzyme -a type of protein that speeds up the rate of a chemical reaction in your body - some reduce the amount of energy needed for a chemical reaction to begin

4. 7. enzymes in digestion -amylase- made in glands near mouth, help speed up breakdown of complex carbs - pepsin- in stomach, breaks down complex proteins - pancreas releases enzymes into small intestine- some break down starches, some break down fats, and some break down proteins 8. organs of the digestive system - mouth, esophagus, stomach, small intestine, large intestine, rectum, and anus 9. accessory organs - tongue, teeth, salivary glands, liver, gallbladder, and pancreas

5. 10. mouth -mechanical digestion- chew your food - chemical digestion- food mixes with saliva - saliva- mostly water, also mucus and an enzyme that breaks down starch into sugar - food is moved by tongue to back of mouth, swallowed, and passes into esophagus 11. esophagus -muscular tube about 25 cm long - takes 4 to 6 seconds for food to move through esophagus into stomach - mucous glands keep food moist, smooth muscle keeps food moving down by squeezing 12. peristalsis - waves of muscle contractions that move food through the entire digestive tract

6. 13. stomach -a muscular bag with folds on the inside - mechanical digestion- food is mixed in stomach by peristalsis - chemical digestion- food mixed with enzymes and digestive solutions to break it down -acidic solution destroys bacteria in food - food moves through stomach in 2 to 4 hours and is changed to chyme 14. chyme -thin, watery liquid made from stomach breaking down food, moves from stomach to small intestine

7. 15. small intestine -small in diameter, 4 to 7 meters long - first part called duodenum- most digestion takes place here, bile from liver is added to food and breaks up fat particles - digestive solution from pancreas contains bicarbonate ions and enzymes- neutralize stomach acid - pancreas makes insulin which allows glucose to pass from bloodstream into cells - absorption takes place in folds and villi - nutrients move from villi into blood and to cells - undigested and unabsorbed food move into large intestine 16. villi - fingerlike projections on folds in small intestine

8. 17. large intestine -main job is to absorb water from the undigested mass in chyme - chyme can stay here for up to 3 days - rest of undigested food becomes more solid and passes through rectum and out through the anus 18. bacteria -bacteria is not always harmful - in large intestine feed on undigested material and make vitamins you need - breakdown of intestinal materials by bacteria produce gas