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2012-10-18 19:52:36

Chapter 8
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  1. Ingestion
    - intake of food via the mouth
  2. Digestion
    - mechanically or chemically breaking down food into their subunits
  3. Absorption
    - movement of nutrients across the GI tract wall to be delivered to cell via the blood
  4. Elimination
     - Process of expelling substances from the body
  5. Defecation
     - Discharge of feces from the rectum through the anus
  6. Enzymes
    - Specialized proteins
  7. Bolus
    - mass of chewed food
  8. Peristalsis
    - rhythmic wavelike contractions that propel substances along a tubular structure
  9. epiglottis (S and F)
    • - S: elastic cartilage
    • F:covers the voice box to make sure food is routed into the esophagus.
  10. Give the overall structure involved in the digestive system and its main functions.
    • mouth- teeth chew food;
    • tongue tastes and pushes food for chewing and swaloowing
    • pharynx- passageway where food is swallowed
    • esophagus- passageway where peristalsis pushes food to stomach
    • stomach- secretes acid and digestive enzymes for protein, churns mixing food w/secretions
    • small intestine- mixes chyme w/ digestive enzymes for final breakdown; absorbs nutrients molecules into body; secretes digestive hormones into blood
    • large intestine- absorb water and salt to form fecescolon-eliminates toxins in the intestines, blood and lymph systems.
    • rectum- stores and regulates elimination of feces
    • anus- expells feces
  11. List and describe the two types of digestion and the organs/substances involved in each.
    • 1- mechanical - physical methods
    • 2- chemical - requires enzymes
  12. List and describe the 4 layers found in the organs and parts of the GI tract.
    • 1- mucosa - innermost layer that produces mucus that protects the lining and also produces digestive enzymes
    • 2- submucosa- 2nd layer of loose connective tissue that contains blood vessels, lymphatic vessels, and nerves
    • 3- muscularis - 3rd layer made of 2 layers of smooth muscle that move food along the GI tract
    • 4- serosa - outer lining that is part of the peritoneum (epithelial)
  13. Which parts of the GI tract are mainly involved in digestion, absorption, and elimination?
    • Digestion - mouth, pharynx, esophagus, stomach
    • Absorption - small intestine
    • Elimination - large intestine, colon/rectum, anus
  14.  Describe the things within the mouth and their role in digestion.
    • 1- 3 pairs of salvary glands - begin carb digestion
    • 2- tonsils -fight disease
    • 3- teeth - mecanical breakdown of food
    • 4- tongue - taste buds, assists in the mechanical breakdown and movement of food
  15.  List and describe the 2 phases of swallowing.
    • 1- voluntary phase - from the mouth into the pharynx
    • 2- involuntary phase - becomes a reflex
  16. Pharynx ; S&F
    • S: is a cavity between the mouth and esophagus
    • F:  that serves as a passageway for food (and air)
  17. Esophogus ; S&F
    • S:  is a long, muscular tube
    • F:  carries food to the stomach
  18. Stomach ; S&F
    • S:  J-shaped organ, thick muscular wall, wall and deep folds and gastric pits
    • F: stores food (2-6 hours) ,Churns food – mechanical digestion,Secretes gastric juice (pepsin, HCl, mucus) – chemical digestion
  19. Small Intestine ; S&F
    • S:Long tube from stomach to large intestine,Averages 6m (18 ft) in length, Has ducts coming from pancreas, gallbladder, Hasvilli (finger like porjections of the intestine);
    • F:Digestion (ezymes frompancreas and Bile from gall baldder) Absorbtion (villi)
  20. Large Intestine ; S&F
    • S: Includes the cecum (beginning), colon (allthe middle), rectum (ending) and anal canal, Larger in diameter but shorterthan the small intestine;
    • F:Absorb water to prevent dehydration,Absorbsvitamins (B complex and K) produced by intestinal flora (good bacteria), Formsand rids the body of feces through the anus
  21. Pancreas ; S&F
    • S: Fished-shaped spongy exocrine gland behindthe stomach;
    • F: digestion, buffers, sugar control
  22. Gallbladder ; S&F
    • S: small organ under the right lobe of the liver;
    • F: store and release bile
  23. Liver ; S&F
    • S: Large organ that lies under the diaphragm andis made of 100,000 lobules;
    • F: Filters blood, removes iron, vitamins, storesglucose as glycogen, makes plasma proteins, makes bile, breaks down hemoglobin
  24. Explain how the S/V ratio is so large in the small intestine.  Why is that important?
    Absorption is slow, so the increased S/V ratio allows absorption of nutrients.
  25. Be able to list the major facts associated with each of the following Disorders: (the information underlined in the power point)
    • a. Gas swallowing air or during the breakdown process of certain foods by the bacteria that is present in the colon.
    • b. lactose intolerance lack an enzyme that is called lactasec.      
    • c. ulcers Ulcers are holes in the GI tract; The mucous lining that normally protects the stomach from digestion must be compromised for an ulcer to developd.     
    • d. diarrhea watery stool, Caused by:Irritation of the intestine; Usually related to a bacterial or viral infectione.      
    • e. constipation Infrequent bowel movements due to hard, dry stool; Caused by:Lack of fiber. 
    • f. colorectal cancer Cancer of the colon or rectum; Colorectal cancer is the second leading cause of death by cancer in the U.S.A.; Caused by polyps – polyp growth directly related to diet and/or constipationg.      g. stomach cancer Helicobacter pylori infection and a poor diet
    • h. liver disorders                                                              i.      jaundice When bile pigments leak to blood                                                         
    •    ii.      hepatitis Infection of the liver, usually viral                                                       
    •    iii.      cirrhosis Chronic disease of the liver