Digestive+System-PK

Digestive System Book Homework (p.144-155) 1. Name and describe the processes that occur during the digestive process. - Ingestion: The mouth consumes food. - Digestion: The mechanical and chemical process that occurs when the food is physically divided into pieces and then chemically proken down by digestive enzymes. This occurs in the mouth and the stomach. - Movement: The movement of the food thoughout the digestive organs and their expulsion/ - Absorbtion: The unit molecules (for example: nutrients) that are produced by digesion cross the GI tract wall and enter the tract lining cells which enter the blood for the delivery to other cells.

2. What are the four layers of the GI tract? Associate an illness with each of the layers. (Describe the Illness) The four layers are the mucosa, submucosa, muscularis and the serosa. Diverticulosis is a disease where the first layer of mucus can leak through holes in the digestive tract and created pouches that can be infected or inflamed. The submucosa contains lymphe nodules that have blood vessels which can become inflamed created inflammatory bowel disease. The muscularis can be associated with irritable bowel syndrome which is characterized by chronic diarrhea, bowel disease, fever and weight loss.

3. Describe the mechanical digestion and the chemical digestion that occurs in the mouth. The mouth mechanically digests food through breaking it down by using the teeth and tongue. The mouth chemically digests food through saliva which contains enzymes that begins the break down of starch digestion.

4. What ordinarily prevents food from entering the nose or entering the trachea when you swallow? The soft palate moves to cover nasal pasages an the epilottis covers the glottis (opening to the larynx and the air passage).

5. What are the function of the stomach, and how is the wall of the stomach modified to perform these functions? The stomach stores food, begins the protein digestion and controls the movement of chyme into the small intestine. The stomach walls have four layers. The muscularis layer mechanically breaks up food through it's three layers of muscles. The mucosa layer releases gastrc juice which contains enzymes that digest protin, hydrochloric acid and mucus.

6. What are the functions of the small intestine and how is the wall of the small intestine modified to perform these functions? The small intestines completes the digestion and absorbs nutrients. The small intestines wall produces enzymes that digest all types of foods, such as bile to disperse fats. The Wall of the small intestine absorbs moleculs through the mucosa wall through millions of villi projections.

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

8. How does each accessory organ contribute to the digestion of food? The pancreas produces sodium nicarbonate and digestive enzymes to break down all types of food. The liver recieves blood from the GI tract and flters the capillaries to remove poisonous substanes from the blood. The gallbladder produces bile.

9. What are the different parts of the large intestine? The cecum, the colon, the rectum and the anal canal.

10. What are the functions of the large intestine? The large intestine absorbs water, vitamins and forms feces.