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Download liver, gall bladder & pancreas © 2006 Plano ISD, Plano, TX
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© 2006 Plano ISD, Plano, TX Digestive System a coiled, muscular tube (6-9 meters long) beginning with the mouth and ending with the anus The main role of the digestive system is to break down and absorb nutrients that are necessary for growth and maintenance. © 2006 Plano ISD, Plano, TX The Path of Digestion • • • • • • • Mouth Esophagus Stomach Small intestine Large intestine Rectum Helpers are: liver, gall bladder & pancreas © 2006 Plano ISD, Plano, TX Digestion process by which food is converted into soluble forms 2 forms of digestion physical or mechanical © 2006 Plano ISD, Plano, TX chemical Forms of Digestion Physical Digestion Chemical Digestion mechanical chemical breakdown of food breakdown of food into smaller particles by enzymes begins in mouth begins in mouth with saliva by chewing – teeth and tongue increases surface mostly occurs in area of food small intestine © 2006 Plano ISD, Plano, TX Physical Digestion mechanical begins in mouth by chewing © 2006 Plano ISD, Plano, TX Chemical Digestion chemical begins in mouth with saliva Stages of Digestion movement propels food through system secretion breakdown of food into molecular sizes food molecules passing absorption through intestinal walls elimination removal of undigested food release of digestive juices digestion © 2006 Plano ISD, Plano, TX Primary Digestive Organs © 2006 Plano ISD, Plano, TX begin the mechanical breakdown of food esophagus - transports food to stomach through the process of stomach - muscular peristalsis organ that stores, mixes, digests and controls passage of food teeth mouth tongue © 2006 Plano ISD, Plano, TX Esophagus • Moves food from the back of throat to the stomach • Epiglottis – flap of skin that covers windpipe (trachea), keeping food out of lungs • Valve at the end of the esophagus (sphincter) allows food to pass into the stomach but not back into the esophagus • Takes about 8-10 seconds to move bolus (chewed food) from swallowing to stomach © 2006 Plano ISD, Plano, TX Peristalsis esophagus food stomach © 2006 Plano ISD, Plano, TX series of involuntary muscular contractions in the esophagus that squeeze the food down to the stomach From the esophagus to the Stomach Click on picture to show video © 2006 Plano ISD, Plano,http://www.gastrointestinalatlas.com TX Stomach • Muscular walls of stomach contract to churn and mix the food with gastric juices • Gastric juices (hydrochloric acid and pepsin with mucus) - begin the break down of proteins • Chemical and mechanical digestion takes about 2 to 3 hours • Mixture of partially digested food is called chyme © 2006 Plano ISD, Plano, TX small intestines coiled tube from 3 6m long, the major site for digestion and absorption of nutrients; contain villi large intestines 1.5 m long tube, absorbs water from undigested material anus - opening for removal of feces © 2006 Plano ISD, Plano, TX Small Intestine • Chyme is flooded with enzymes • Enzymes help break down the nutrients to basic forms • Liver produces bile (stored in the gall bladder) – a salt that helps break down fats • Villi - finger like projections in the wall of the small intestines where blood vessels absorb nutrients into the bloodstream © 2006 Plano ISD, Plano, TX Large Intestine • Undigested material (fiber, water, and un-digestible substances) moves into the large intestine or colon • Water is removed and undigested material reduced to a solid waste called feces • Colon contains bacteria to help final digestion • Feces (yes, poop) is stored in the rectum and eliminated © 2006 Plano ISD, Plano, TX Elimination • Undigested waste is moved into the rectum where it is eliminated through the anus • Peristalsis – the muscular contractions that move food through your digestive system © 2006 Plano ISD, Plano, TX Accessory Digestive Organs © 2006 Plano ISD, Plano, TX salivary glands secrete a chemical (enzyme) that breaks down into bile, produces liver -starch glucose which helps break down fats in small intestines gall bladder - stores bile © 2006 Plano ISD, Plano, TX pancreas - secretes enzymes that break down starches and proteins The Liver (& Gall Bladder) • Liver produces bile to help with chemical digestion • Bile stored in the gall bladder (then sent to beginning of small intestine) • The liver filters harmful substances or wastes, turning some of the waste into more bile • The liver helps figure out how many nutrients will go to the rest of the body, and how many will stay behind in storage. – For example, the liver stores certain vitamins and a type of sugar your body uses for energy. © 2006 Plano ISD, Plano, TX Accessory Digestive Organs connected to stomach by ducts liver pancreas gall bladder © 2006 Plano ISD, Plano, TX Pancreas • Produces some digestive enzymes © 2006 Plano ISD, Plano, TX © 2006 Plano ISD, Plano, TX ulcers spot in stomach lining where cells are destroyed, lining unprotected, irritated by stomach acid gastritis swelling of stomach lining, caused by irritating foods, alcohol, or bacteria acid reflux "back washing" of acid from the stomach into the esophagus; also called heartburn © 2006 Plano ISD, Plano, TX Chemical Digestion Mouth - chemical digestion begins in the mouth with saliva (spit) Stomach - gastric juices (stomach acid, mucus, enzymes) begin to break down the food to smaller molecules Small intestine – food broken down even more so your body can absorb the nutrients ** Most digestion occurs in the small intestine – fats, proteins, and carbs. Large intestine – bacteria help with final stage of digestion © 2006 Plano ISD, Plano, TX Nutrients • Carbohydrates: starches and sugars • Proteins: simplest form is amino acids • Fats : absorbed as fatty acids (with the help of bile from the liver) • Vitamins & Minerals • Water © 2006 Plano ISD, Plano, TX Enzymes Enzymes are proteins that help chemical digestion Enzymes help a chemical reaction without being changed itself Found in raw fruits and vegetables Also produced in the stomach, small intestine and pancreas © 2006 Plano ISD, Plano, TX © 2006 Plano ISD, Plano, TX 1. 2. 3. 4. © 2006 Plano ISD, Plano, TX 5. 6. 7. 8. 9. 10. 1. mouth 2. esophagus 3. 3. stomach 4. small intestine 5. large intestine © 2006 Plano ISD, Plano, TX 6. anus salivary glands 1. liver 2. 3. bladder gall pancreas 4. © 2006 Plano ISD, Plano, TX 1. 2. 3. 4. 5. © 2006 Plano ISD, Plano, TX 6. 1. 2. 3. 4. © 2006 Plano ISD, Plano, TX Match the structure with the number. © 2006 Plano ISD, Plano, TX salivary small large gall esophagus pancreas stomach liver anus bladder intestine intestine glands Match the function with the number. contains major enzymes organ forfor secretes transports stores mixes the 4 undigestible and accessory enzymes food stores by for digestion stores bile theproduces first andchemical absorption contains villi bile starch digestive peristalsis food breakdown organs of nutrients of food breakdown © 2006 Plano ISD, Plano, TX
