Once again we have been miniaturized in the submarine to continue the fantastic journey of the digestive system. We will visit a 55 year old man. The host will have a burger, fries and a root beer. We will follow lunch throughout the digestion process. Digestion is the process of transforming consumed food into energy necessary for survival and involves the creation of waste for elimination. (Mohan, 2010). The digestive tract is a long, twisted tube that begins at the mouth and ends at the anus, called the digestive tract. The wall of this tube is made up of four layers of fabric. The layers are listed from the inner tunic to the outer tunic: mucosa or mucous membrane, submucosa, muscularis, and serosa. The hollow space inside the digestive tract is called the lumen. (Thibodeau & Patton, 2008).We will begin the visit with entry into the oral cavity. The mouth is a hollow chamber with a roof, floor, walls, teeth for grinding food and lined with mucous membrane. Mucus produced by the lining of the gastrointestinal tract protects the epithelium from digestive juices and lubricates food passing through the lumen. Digestion begins in the mouth before you even take the first bite of the meal. Odors trigger the secretion of saliva from the salivary glands. (Mohan, 2010). There are three pairs of salivary glands; these are the parotids, the submandibular and the sublingual. (Thibodeau and Patton, 2008). Saliva increases when you actually taste the food. Once you begin to chew and break down food, more saliva is produced to begin the process of breaking down the food into a form that your body can absorb and use. Food undergoes three types of transformations in the body: digestion, absorption and metabolism. (Mohan, 2010). Our first stop after middle of paper......important jobs but still working so close together, providing nutrients and elimination to maintain homeostasis. Looks like we're ready to move out, so I hope you enjoyed the tour and don't hesitate to ask any questions. Good day. Works Cited Mohan, V. (2010). The digestive system: the journey of food through the digestive system. WebMD. Retrieved from http:www.webmd.com/digestive-disorders/digestive-system Thibodeau, GA and Patteon, KT (2008). Structure and function of the body (13th ed.). St. Louis, MO: Mosby/Elsevier. EXPERT in anatomy, (nd). Detail of the structure. EXPERT in anatomy. Retrieved from http://www.anatomyexpert.com/structure_detail/8920/32838/Cardiovascular System, (nd) Circulation. Retrieved from http://www.anatomy.tv/StudyGuides/StudyGuide.aspxThe Digestive System, (nd) The Digestive System. Retrieved from: http://www.anatomy.tv/StudyGuides