Digestive+System+CH

=**Digestive System**= = =
 * SCI Human Biology - 2**
 * Assigned: 1/9 Due: 1/10**



1. Name and describe the processes that occur during the digestive process.
 * Digestive System Book Homework (p.144-155)**
 * __Ingestion__: when you take food in through your mouth and break it down with teeth.
 * __Digestion:__ either mechanical or chemical. Mechanical digestion is when food is broken down into pieces by digestive enzymes in mostly the mouth and stomach. Chemical digestion is when food begins in the mouth and does not finish the process until the small intestine.
 * __Movement:__ when food transfers from one organ to the next.
 * __Absorption:__ when the food has left the GI tract, and then the nutrients are able to move into the blood to move throughout the body.
 * __Elimination:__ when the unneeded nutrients exit the body.

2. What are the four layers of the GI tract? Associate an illness with each of the layers. (Describe the Illness) 1. Mucosa, which can cause Diverticulosis where parts of the muscosa push through other layers. 2. The GI wall called submucosa, which can cause inflammatory bowel disease (IBD) where the the infected person causes chronic diarrhea, abdominal pain, fever, and weight loss. 3. Muscularis, which can cause irritable bowel syndrome (IBS) where the infected person suffers abdominal pain, constipation, and/or diarrhea. 4. Serosa, which is associated with the appendix. If the appendix become inflamed, it must be removed because if it ruptures it will cause a life-threatening infection of peritoneum.

3. Describe the mechanical digestion and the chemical digestion that occurs in the mouth. -Mechanical digestion -People start with baby feet and eventually get thirty-two teeth including molars. -Chemical digestion -Glands sends saliva into the mouth. The enzyme saliva breaks down the food in the mouth. 4. What ordinarily prevents food from entering the nose or entering the trachea when you swallow? The soft palate of the mouth stops food from entering the the nose, and the epiglottis stops food from going down 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? The stomach stores food, initiates the digestion of protein, and controls the movement of chyme into the small intestine. The wall of the stomach has four layers, and two of them are modified for different purposes. The extra layers moves obliquely to the other layers. 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 intestine completes digestion and absorbs nutrients. It takes care of all the functions involving digestion, nutrients, and gets nutrients to the elimination stage. 7. What are the three main accessory organs that assist with the digestive process? The pancreas, liver, and gallbladder. 8. How does each accessory organ contribute to the digestion of food? The pancreas makes juices that assist with digestion. The liver cleans blood and helps with waste. The gallbladder produces bile to help breakdown nutrients in digestion. 9. What are the different parts of the large intestine? The large intestine is made up by the rectum, cecum, anal canal, and the colon. 10. What are the functions of the large intestine? The large intestine re-absorbs water and maintains the fluid balance of the body, absorbs some vitamins, processes undigested material, and stores waste before it is elminiated.