1. Digestive System Yixuan He

2. Function Break up food into smaller pieces. Transporting food to the GI tract (gastrointestinal) Secreting digestive enzymes Absorbing nutrients into the blood Excreting solid waste products (waste)

3. Mouth The mouth is the beginning of the digestive tract Chewing breaks the food into small pieces Easily digested

4. Pharynx and Esophagus Pharynx The throat Receives the food from your mouth. Swallowing A voluntary reflex Esophagus Connects mouth to stomach A muscular tube extending from the pharynx and behind the trachea to the stomach Food is pushed through the esophagus and into the stomach by means of a series of contractions called peristalsis.

5. Stomach Storage bag for food Secretes acid and powerful enzymes that bread down the food and change it to a consistency of liquid or paste. Flexible Expands when you eat Can hold up to 3 L of food If the stomach could not store food, you would have to eat every twenty minutes or so instead of just three times a day.

6. Small Intestine folded into tiny fingerlike projections called villi Each villus contains blood vessels. surface area through which nutrients pass to the bloodstream is greatly increased If the villi on the inner lining of the small intestine are flattened out, they would cover about 4500 square meters. Where most of the nutrient is absorbed through the walls and into the bloodstream Breaks down food Duodenum, Jejunum, and Ileum Duodenum is largely responsible for the continuing breakdown process Jejunum and ileum being mainly responsible for absorption of nutrients into the bloodstream.

7. Large Intestine (colon) five- to seven -foot -long muscular tube that connects the small intestine to the rectum absorb water from the undigested food, hold the undigested food for a while and then excrete it as feces. Consists of: cecum ascending colon transverse colon descending colon sigmoid colon

8. Rectum and Anus Rectum receives stool from the colon stores some feces and help with defecation Anus dispose of waste products out of the body

9. Accessory organs Salivary Glands Liver Pancreas Gallbladder Sphincters

10. Salivary Glands Saliva mixes with food to begin the process of breaking it down. Fun fact: The smell of food triggers the salivary glands in your mouth to secrete saliva, causing your mouth to water. When you actually taste the food, saliva increases.

11. Liver and Pancreas Liver The largest organ inside the body It produces bile, a substance that helps in the digestion of fats. Process the blood coming from the small intestine. Purifies this blood of many impurities before traveling to the rest of the body. Pancreas Produce pancreatic juice Pancreatic juice helps in neutralizing or weakening the acid in food inside the stomach. Also contains different enzymes that are needed to further break down starch, proteins and fats in the small intestine.

12. Gallbladder and Sphincters Gallbladder Small muscular sac Storage sac for excess bile. Sphincters Lower Esophagus Sphincter Located Just before the opening to the stomach Ring-shaped muscle This sphincter opens to let food pass into the stomach and closes to keep it there. If your LES doesn't work properly, you may suffer from a condition called GERD which causes heartburn and regurgitation anal sphincters (inner and exterior) control the exit of feces from the body

13. Physical digestion vs. Chemical digestion Physical is the breakdown of food by physical means. Chemical molecules of water, vitamins, and minerals are small enough to be absorbed through the intestinal wall and into the blood stream proteins, carbohydrates, and fat molecules are too large and must be broken down further by chemical means. This is chemical digestion.

14. Physical digestion vs. Chemical digestion Physical Chemical breakdown of food by physical means Chewing and churning breakdown of food by chemical means Acids and enzymes Digest food and aid in absorbing nutrients.

15. Nutrients Carbohydrates: Saliva begins carbohydrate digestion with the enzyme salivary amylase. The release of Pancreatic Amylase in the duodenum digests the rest Protein Begins in the stomach with HCl and Pepsin. Inside the small intestine, the pancreatic enzymes trypsin and chymotrypsin break down the polypeptides. Lipid The fat digesting enzyme lingual lipase starts breaking down fat inside your mouth as you are chewing. Bile released from the gall bladder

16. Crohn’s Disease a chronic inflammatory condition of the gastrointestinal (GI) tract. Symptoms: abdominal pain diarrhea weight loss poor appetite Crohn’s disease may affect as many as 700,000 Americans. Crohn's is more prevalent among adolescents and young adults between the ages of 15 and 35. Treatment: Medication Surgery

17. Irritable Bowel Syndrome (IBS) Irritable bowel syndrome is a functional gastrointestinal (GI) disorder, meaning it is a problem caused by changes in how the GI tract works. Symptoms Diarrhea Constipation Passing mucus Abdominal bloating Affects 3 to 20 percent of the population Treatment: Changes in eating, diet, and nutrition Medication Probiotics

18. Bibliography National Digestive Diseases Information Clearinghouse (Division of NIDDK/NIH). American Medical Association. The Cleveland Clinic Foundation http://my.clevelandclinic.org/anatomy/digestive_system/hic_the _structure_and_function_of_the_digestive_system.aspx http://my.clevelandclinic.org/anatomy/digestive_system/hic_the _structure_and_function_of_the_digestive_system.aspx Crohn's and Colitis Foundation of America National Digestive Diseases Information Clearinghouse http://digestive.niddk.nih.gov/ddiseases/pubs/ibs/

19. Bibliography (Cont.) Pictures: http://www.google.com/imgres?hl=en&sa=X&tbo=d&biw=1052&bih=535&tbm=isch&tbnid=R9Klud4RSyZ2XM:&imgrefurl=http://www.encognitive.com/node/1122&docid=XQFBGcRLNkvv GM&imgurl=http://www.encognitive.com/images/digestive-system- 2.jpg&w=422&h=561&ei=r6sAUdveDMaK2gWyj4HoDA&zoom=1&iact=hc&vpx=451&vpy=137&dur=794&hovh=259&hovw=195&tx=125&ty=138&sig=113692303009654574651&page=1&t bnh=153&tbnw=121&start=0&ndsp=14&ved=1t:429,r:3,s:0,i:160 http://www.google.com/imgres?hl=en&sa=X&tbo=d&biw=1052&bih=535&tbm=isch&tbnid=jWClj- 7x4y8kMM:&imgrefurl=http://en.wikipedia.org/wiki/Human_pharynx&docid=Ce2Gcs2udEo3eM&imgurl=http://upload.wikimedia.org/wikipedia/commons/thumb/d/d4/Illu01_head_neck.jpg/250px- Illu01_head_neck.jpg&w=250&h=254&ei=FawAUdnWLqiG2gXFpICwDg&zoom=1&iact=hc&vpx=4&vpy=158&dur=4080&hovh=203&hovw=200&tx=76&ty=119&sig=11369230300965457465 1&page=1&tbnh=139&tbnw=146&start=0&ndsp=18&ved=1t:429,r:0,s:0,i:151 http://www.google.com/imgres?hl=en&tbo=d&biw=1052&bih=535&tbm=isch&tbnid=uRaNeVBRR10iYM:&imgrefurl=http://uogirl10-virtualfieldtrip.blogspot.com/2008/05/post- 8.html&docid=vOXad7FMIKH2fM&imgurl=http://2.bp.blogspot.com/_pGhDYqqlW5U/SCJvbH59zKI/AAAAAAAAACs/BVCq11bhi4U/s400/Stomach.gif&w=300&h=243&ei=TKwAUbavC- js2AXekoDwDg&zoom=1&iact=rc&dur=359&sig=113692303009654574651&page=1&tbnh=149&tbnw=187&start=0&ndsp=11&ved=1t:429,r:8,s:0,i:172&tx=120&ty=88 http://www.google.com/imgres?um=1&hl=en&sa=N&tbo=d&biw=1052&bih=535&tbm=isch&tbnid=ibjJ20Hhr_6vfM:&imgrefurl=http://students.cis.uab.edu/ashjones/index3a.html&docid =VbAAZkvKEOsP9M&imgurl=http://students.cis.uab.edu/ashjones/colon3.jpg&w=396&h=300&ei=rKwAUZSxNuX72QWi54GYAw&zoom=1&iact=rc&dur=465&sig=113692303009654574651 &page=1&tbnh=134&tbnw=177&start=0&ndsp=11&ved=1t:429,r:3,s:0,i:160&tx=127&ty=59 http://www.google.com/imgres?um=1&hl=en&sa=N&tbo=d&biw=1052&bih=535&tbm=isch&tbnid=BAURNyL0fQZLwM:&imgrefurl=http://www.alargastro.com/Patient_Education/Large_I ntestine.html&docid=v6ZGgB1mjYNowM&imgurl=http://www.alargastro.com/images/Large%252520Intestine.jpeg&w=460&h=300&ei=Ba0AUdWPC4rm2QWkl4DADg&zoom=1&iact=hc& vpx=569&vpy=217&dur=1733&hovh=181&hovw=278&tx=211&ty=116&sig=113692303009654574651&page=1&tbnh=133&tbnw=204&start=0&ndsp=16&ved=1t:429,r:8,s:0,i:175 http://www.google.com/imgres?um=1&hl=en&tbo=d&biw=1052&bih=535&tbm=isch&tbnid=cBPuui51denENM:&imgrefurl=http://www.cpmc.org/advanced/liver/patients/topics/Pancrea sCancer-profile.html&docid=lqQQGXFzlRNj3M&imgurl=http://www.cpmc.org/images/liver/topics/PancreasCancer-profile- 0.jpg&w=260&h=288&ei=Uq0AUYLxCorm2QWkl4DADg&zoom=1&iact=hc&vpx=803&vpy=140&dur=1788&hovh=230&hovw=208&tx=177&ty=110&sig=113692303009654574651&page=1& tbnh=144&tbnw=130&start=0&ndsp=18&ved=1t:429,r:17,s:0,i:133