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Upper Digestive System Study Guide By : Sibhat Hagos, Theodore Wilson, Justice Smith, David Heim, and Daulton Sink Theodore Wilson 13 February 2009 Mouth - The mouth is the first stop in the digestive system - Teeth breakdown the food into smaller pieces and saliva from your salivary glands extract the nutrients from the food - The saliva used to extract nutrients is also used to moisten up the food to ease swallowing - When the food is ready for swallowing, the soft palate closes off nasal passages to prevent the food from entering your nostrils. - There are three main salivary glands in your mouth: - - Submandibular – produces most of the saliva used in the digestive process a mixture of serous and mucous saliva Parotid – produces serous saliva Sublingual – produces mucous saliva David Heim 13 February 2009 Esophagus - Straight collapsible tube about the 25 centimeters long Extends from the mouth/throat to the stomach. Lubricated with mucus so that food can slide through it more easily. The esophagus is basically just a tube that food is transported down once it gets chewed up in the mouth and needs to be sent to the stomach. - Once the food goes through the throat, it faces a fork in the road. One pipe is the trachea and one is the esophagus. - The epiglottis is flap of tissue that tries to prevent food from going down the trachea instead of the esophagus. -like in pinball when the little lever comes down to prevent the ball from going down that section. Food moves through not by gravity but by having your muscles contracting and relaxing. Pushing the food down. We know that because astronauts in zero gravity were still able to swallow food. Once the food reaches the end of esophagus it has to go through the cardiac sphincter. This is where the esophagus meets the stomach. -These fibers are normally contracted so that the food in the stomach is not regurgitated -They relax to allow food in and out of the stomach. The esophagus works similarly to how you get toothpaste out of a toothpaste tube. Sibhat Hagos and Justice Smith 13 February 2009 Stomach - A flexible, muscular bag the size of your fist but can expand up to 20 times its size - Upper stomach connects to esophagus ( Lower esophageal sphincter or cardiac sphincter ) - Lower stomach connects to small intestine ( Pyloric sphincter ) The stomach is divided into three parts. - - The Reservoir ( Fundus ) – holds undigested food The Mixer – is made-up of three layers of muscle that pulverize food and along with gastric acid turn the food into chyme, a thick fluid mass of partially digested food and gastric secretions. The Funnel ( Antrum ) – empties the chime into the small intestine Gastric acid = Hydrochloric acid + Pepsin ( an enzyme ) The reason why your body’s gastric acid does not burn through your stomach is because your stomach constantly secretes mucus, which neutralizes the effects of the acid on your stomach. Gurgling happens because your mind knows when your body needs nutrition and when its time and your stomach has nothing in it it starts contracting causing the gurgling you hear. The stomach is comparable to a refinery. Just as ore is refined to extract the mineral within your stomach breaks down food to extract the nutrients. Daulton Sink 13 February 2009 Upper Digestive Disease Gastritis – an inflammation of the mucous membrane lining your stomach. Sores and raw areas can develop as a result of this inflammation. Gastritis is caused by either the ingestion of an irritating substance ( bacteria/ viral ) or from stress caused by a bad wound around the stomach area. Symptoms include: - Bleeding in affected areas - Blood in the stool - Vomiting Diseases associated with gastritis include: - Alcoholism - Food allergies - Cohn’s disease - Hiatus Hernia Gastritis can be avoided by good dietary habits. Prescriptions for bismuth subsalicylate, a medicine that temporarily treats discomforts of the stomach and gastrointestinal tract, more commonly known as Pepto-Bismol, can be used to treat an already existing case. Antibiotics and 24 hours of consuming no food are other ways to treat gastritis. Simon Gigli 13 February 2009 Calculate You Calorie Intake Metabolic Rate: a person’s biggest daily calorie intake Calorie: a term for the energy content of food - some foods dense in energy like butter - celery has a negative calorie intake, it takes more energy to digest it than it actually gives - foods with more calories will give you more energy Mifflin – St. Joer Equation 9.99(w) + 6.25(h) – 4.92(a) = RMR ( Resting Metabolic Rate ) w = weight h = height a = age Men add 5 to final result Women subtract 161 from final result In addition to RMR calories, each person need additional calories for exercise. - muscle has higher calorie needs than fat tissue, so people with more muscle burn more calories at rest than people with more fat WORKS CITED "Anatomy of the Upper Digestive System - Medical Illustration, Human Anatomy Drawing." Nucleus Medical Art. 1999-2009. 10 Feb. 2009 <http://catalog.nucleusinc.com/generateexhibit.php?ID=9751>. Biggs, Alton. Biology: The Dynamics of Life. Columbus, Oh: Glencoe/Mcgraw-Hill, 2004. Children's hospital of Pittsburgh of UPMC. "Viruses, Bacteria, and Parasites in the Digestive Tract." Inflammatory and Infectious Diseases. 03 Feb. 2008. 10 Feb. 2009 <http://www.chp.edu/CHP/P02019>. NIH, Inc. "Your Digestive System and How it Works." Digestive Diseases A-Z List of Topics and Titles. Apr. 2008. 10 Feb. 2009 <http://digestive.niddk.nih.gov/ddiseases/pubs/yrdd/>. "Problems Affecting the Upper Digestive Tract." Digestive and Liver Disorders. 2008. The Rector and Visitors of the University of Virginia. 10 Feb. 2009 <http://www.healthsystem.virginia.edu/uvahealth/peds_digest/upperdig.cfm>. Shier, David. Butler, Jackie. Lewis, Ricki. Hole’s Essentials of Human Anatomy and Physiology. Published by McGraw Hill. Copyright 2006. pages 390 and 396.
