Digestive+System+AG

Allie Gruber Human Bio Field Period 1 September 3, 2008

8.1 Overview of Digestion 1. Name and describe the three processes that occur during the digestive process. The processes of digestion require ingestion which occurs when the mouth takes in the food, digestion when food is divided into pieces that can be acted on by the digestive enzymes, and absorption which occurs as a unit molecules produced by digestion.

2. What are the four layers of the GI tract? Associate an illness with each of the layers. Describe the illness. Mucosa is the inner mucous membrane layer that is modified according to the digestive organ. Diverticulitis is a condition in which portions of the mucosa have pushed through the other layers and formed pouches where food can collect and often become infected or inflamed. Submucosa is a broad band of loose connective tissue that contains nerves, blood and lymphatic vessels. Inflammatory bowel disease is the resulting illness that is characterized by chronic diarrhea, abdominal pain, fever, and weight loss. Muscularis is the two layers of smooth muscle with the resulting illness of irritable bowel syndrome in which contractions of the wall cause abdominal pain, constipation and diarrhea. Serosa is a thin outermost tissue that is the visceral peritoneum that secrete a serous fluid.

8.2 The First Part of the Digestive Tract

palate: The roof of the mouth that separates the nasal cavities from the oral cavity

salivary glands: sends juices by way of ducts to the mouth

dental carries: occurs when bacteria within the mouth metabolize sugar and give off acids which erode teeth

periodontitis: characterized by a loss of bone and loosening of the teeth so that extensive dental work may be required

Pharynx: a cavity of which food passage and air passage cross

Esophagus: a long narrow tube that takes food to the stomach

Glottis: the opening to the larynx and the air passage

Epiglottis: where the soft palate moves up under to cover the glottis

Peristalsis: a rhythmic contraction that pushes the food along the esophagus and continues in all the organs of the digestive tract

Sphincters: muscles that encircle tubes and act as valves

Diaphragm: muscle that separates the thoracic and abdominal cavities

3. Describe the mechanical and chemical digestion that occurs in the mouth. Mechanical digestion occurs when our teeth chew food into pieces convenient for swallowing.

4. What ordinarily prevents food from entering the nose or entering the trachea when you swallow? The soft palate moves back to close off the nasal passages and the trachea moves up under the epiglottis to cover the glottis

Health Focus Heartburn (p148) 5. What causes the burning sensation associated with heartburn? When the stomach contents pass upward into the esophagus the acidity begins to erode the lining of the esophagus producing the burning sensation.

6. What is GERD? How is it different from heartburn? Gastro esophageal reflux disease is when the reflux is more frequent and remains in the esophagus longer, containing higher levels of acid than in a patient with a typical heartburn or acid reflux.

7. Describe two ways drugs treat GERD. Modifying their eating habits and over the counter medications that neutralize stomach acid

8. Describe ways to avoid heartburn that do not involve drugs. Diet and exercise, avoiding high fat meals, don’t overeat and eating several small meals a day rather than 3 large meals.