Digestive+System+WB

1. Name and describe the processes that occur during the digestive process. 2. What are the four layers of the GI tract? Associate an illness with each of the layers. (Describe the Illness) 3. Describe the mechanical digestion and the chemical digestion that occurs in the mouth. 4. What ordinarily prevents food from entering the nose or entering the trachea when you swallow? 5. What are the function of the stomach, and how is the wall of the stomach modified to perform these functions? 6. What are the functions of the small intestine and how is the wall of the small intestine modified to perform these functions? 7. What are the three main accessory organs that assist with the digestive process? 8. How does each accessory organ contribute to the digestion of food? 9. What are the different parts of the large intestine? 10. What are the functions of the large intestine?
 * Digestive System Book Homework (p.144-155)**

1. In the digestive system, all digestive organs are located in the gastrointestinal tract. The first process is ingestion, which is the act of actually eating the food. Saliva and teeth help to break down the food, so that it can then be passed through the esophagus. Next, actual digestion occurs. Mechanical and chemical digestion occur, causing foods to be broken down into nutrients and passed into the bloodstream, by means of digestive enzymes. All other food materials that are unable to be fully digested are passed through the anus.

2. The first layer of the GI tract is called the Mucosa layer. This layer produces mucus, in order to protect the walls of the GI tracts from harmful digestive enzymes. An illness associated with this layer of the GI tract is referred to as Diverticulitis, which is where mucus pouches become inflamed and infected. The next layer of the GI tract is called the Submucosa layer. This layer contains various blood vessels and nerves, and carries nutrients from the mucosa. The next layer of the GI tract is the Muscularis layer. This layer simply aids in moving food through the GI tract. An illness associated with this layer of the GI tract is referred to as irritable bowel syndrome. The final layer of the GI tract is calle the Serosa. The Serosa secretes serous fluid, which aids in the final stages of digestion. A common illness associated with this layer of the GI tract is Appendicitis, or an enlarged appendix.

3. Mechanical digestion is simply when the teeth break, tear, and grind foods, in order to make them easier to pass through the digestive system. Chemical digestion occurs after mechanical digestion, when saliva, as well as digestive enzymes work to further break down foods.

4. The epiglottis will not allow food to enter the trachea or nasal passages while eating.

5. The function of the stomach is to store partially digested foods, as well as to introduce nutrients from foods into the bloodstream. The stomach is specially modified to perform these functions, because it has a thicker layer of mucus, in order to protect it from harmful stomach acids.

6. The function of the small intestine is to absorb sugar, glycerol, fatty acids, and amino acids molecules. The mucosa of the small intestine is significantly more porous, allowing it to absorb these molecules much more easily.

7. The three main accessory organs that assist with digestive processes are the liver, gallbladder, and pancreas.

8. The liver acts as a filter for the bloodstream, and removes any toxins or other harmful materials from the bloodstream. The gallbladder contains bile, and neutralizes acids in foods. The pancreas contains pancreatic juices, which further aid in breaking down foods.

9. The large intestine consists of the cecum, appendix, colon, rectum, and the anus.

10. The function of the large intestine is to hydrate the body by absorbing water, as well as making fecal matter.