chapter 3 manual.docx

Chapter 3 – Digestion, Absorption, and Transport Learning Objectives After completing Chapter 3, the student will be able to: 3.1 Explain how foods move through the digestive system, describing the actions of the organs, muscles, and digestive secretions along the way. a. List the segments of the d...

Chapter 3 – Digestion, Absorption, and Transport Learning Objectives After completing Chapter 3, the student will be able to: 3.1 Explain how foods move through the digestive system, describing the actions of the organs, muscles, and digestive secretions along the way. a. List the segments of the digestive tract in order from the mouth to the colon. b. Explain the mechanical processes of digestion in order of occurrence in the digestive tract. c. List the five organs and their secretions which assist in the breakdown of food. d. List the secretions that break down carbohydrates. e. List the secretions that break down protein. f. List the secretions that break down fat. 3.2 Describe the anatomical details of the intestinal cells that facilitate nutrient absorption. 3.3 Explain how nutrients are routed in the circulatory systems from the GI tract into the body and identify which nutrients enter the blood directly and which must first enter the lymph. 3.4 Describe how bacteria, hormones, and nerves influence the health and activities of the GI tract. a. Identify the hormones involved in digestive and absorptive processes. 3.5 Outline strategies to prevent or alleviate common GI problems. a. Apply the concepts presented in the chapter to explain common digestive tract problems. Assignments and Other Instructional Materials The following ready-to-use assignments are available in this chapter of the instructor’s manual: Case Study 3: Managing GI Discomfort New! Worksheet 3-1: Chapter 3 Crossword Puzzle1 Worksheet 3-2: Digestion, Absorption, & Transport—DAT2 Worksheet 3-3: Food Habits, Digestion, and Absorption3 Worksheet 3-4: Further Exploration on Digestion (Internet Exercise) New! Critical thinking questions with answers Other instructional materials in this chapter of the instructor’s manual include: Answer key for study card questions Classroom activities Worksheet answer keys (as appropriate) New! Handout 3-1: Peristalsis and Segmentation Handout 3-2: Examples of Hormonal Feedback Loops Visit the book’s instructor companion website to download: Handout 3-3: Transport of Nutrients into the Blood Handout 3-4: The Teeth Lecture Presentation Outline4 Key to instructor resource annotations (shown to the right of or below outline topics): TRA = Transparency acetates: 13e = 13th edition, 12e = 12th edition, 11e = 11th edition, 10e = 10th edition Website = Available for download from book companion website: HN = student handout IM = Included in this instructor’s manual: CS = case study, WS = worksheet, CA = classroom activity Introductory/whole chapter resources: Test Bank; IM WS 3-1, 3-2, 3-4, CA 3-1, 3-3 I. Digestion A. Digestion – Explain the processes of digestion and absorption and describe the challenges associated with digestion, including: 1. Preventing interference between breathing and eating 2. Foods must pass through the diaphragm to enter the stomach 3. Digestive material must continue to move forward 4. The correct amount of fluid must be added to food to prevent foods from moving too quickly or slowly through the gastrointestinal system 5. Enzymes must be able to combine with food to break down products into absorbable fragments 6. The walls of the digestive system must be protected from enzymes that break down food 7. Leftover materials must be voluntarily excreted from the gastrointestinal tract B. Anatomy of the Digestive Tract – Explain and describe the sections of the gastrointestinal (GI) tract including (Figure 3-1): 12e TRA 3; IM CA 3-2 1. Mouth Website HN 3-4 a. Mastication b. Pharynx c. Epiglottis d. Trachea e. Bolus 2. Esophagus 3. Stomach a. Chyme b. Pyloric sphincer 4. Small Intestine a. Gallbladder b. Pancreas c. Duodenum d. Jejunum e. Ileum 5. Large Intestine (Colon) (Figure 3-2) a. Ileocecal valve b. Rectum c. Anus d. Appendix C. The Muscular Action of Digestion – Explain how the muscular action of digestion is under autonomic control; define and explain the following: 10e TRA 23, 24; IM HN 3-1 1. Peristalsis 2. Stomach action: circular, longitudinal, and diagonal muscles (Figure 3-3) 3. Segmentation 4. Sphincter contractions (Figure 3-4) a. Reflux D. The Secretions of Digestion – Describe the secretions involved in digestion, including: 12e TRA 4; 10e TRA 26 1. Digestive enzymes: catalysts in hydrolysis 2. Saliva from the salivary glands (Figure 3-5) 3. Gastric juice a. Gastric glands b. Hydrochloric acid c. pH (Figure 3-6) 4. Pancreatic Juice & Intestinal Enzymes – Pancreatic juice: enzymes and bicarbonate 5. Bile a. Where is it produced b. Where it is stored c. Its action as an emulsifier E. The Final Stage – Explain the final stages of digestion (Figure 3-7) 1. Energy-yielding nutrients 2. Vitamins, minerals, and water 3. Undigested residues 4. Recycling of usable materials II. Absorption – Describe and explain the process of absorption including: 10e TRA 27 A. The types of absorption (Figure 3-8) 1. Simple diffusion 2. Facilitated diffusion 3. Active transport B. Anatomy of the Absorptive System – Describe the anatomical structures involved in absorption 10e TRA 28 1. Villi (Figure 3-9) 2. Microvilli 3. Goblet cells C. A Closer Look at the Intestinal Cells 1. Specialized Cells 2. Food Combining 3. Preparing Nutrients for Transport a. Water-soluble nutrients and small products of fat digestion b. Fat-soluble vitamins and larger fats III. The Circulatory System Website HN 3-3 A. The Vascular System – Explain and describe the vascular system including: consists of arteries, capillaries, and veins (Figure 3-10) 10e TRA 29, 30 1. Arteries 2. Capillaries 3. Veins 4. The hepatic portal vein (Figure 3-11) 5. The hepatic vein B. The Lymphatic System – Explain the lymphatic system including: 1. Lymph fluid 2. The thoracic duct 3. The subclavian vein IV. The Health and Regulation of the GI Tract A. Gastrointestinal Bacteria 1. Flora 2. Probiotics 3. Prebiotics B. Gastrointestinal Hormones and Nerve Pathways 12e TRA 5; IM HN 3-2 1. Explain hormones including: a. Gastin b. Secretin c. Cholecystokinin 2. Describe a negative feedback loop (Figure 3-12) 3. Explain how the pancreas is protected by proenzymes or zymogens C. The System at Its Best – Describe how: IM WS 3-3 1. A healthy digestive tract is essential 2. Sleep, physical activity, and state of mind impact gastrointestinal health 3. Balance, moderation, variety, and adequacy of meals are important V. Highlight: Common Digestive Problems IM CS 3, CA 3-4 A. Choking (Figure H3-1) 1. Food becomes lodged in the trachea 2. The larynx cannot make sounds 3. The Heimlich maneuver may need to be used (Figure H3-2) 4. Strategies a. Take small bites b. Chew thoroughly c. Don’t talk or laugh with food in the mouth d. Don’t eat when breathing hard B. Vomiting 1. Body’s adaptive mechanism 2. Dehydration is a concern 3. May be self-induced as in eating disorders C. Diarrhea 1. Characterized by frequent, loose, watery stools 2. Many causes, including certain foods or medications, IBS, colitis, & celiac disease 3. Irritable Bowel Syndrome – Bloating, abdominal discomfort, GI motility disturbances 4. Colitis – Inflammation of the large intestine 5. Celiac Disease – Autoimmune disease causing inflammation of the small intestine 6. Treatment a. Rest b. Drink fluids c. Medical help is needed if it persists D. Constipation 1. Defecation habits are different among people 2. Many causes are possible 3. Hemorrhoids may be a problem 4. Diverticulosis 5. Diverticulitis (Figure H3-3) 6. Laxatives, enemas, and mineral oil 7. Colonic irrigation 8. Strategies a. High-fiber diet b. Increased fluids c. Exercise regularly d. Respond quickly to the urge to defecate E. Belching and Gas 1. Belching – Strategies a. Eat slowly b. Chew thoroughly c. Relax while eating 2. Intestinal Gas – Strategies a. Commonly caused by carbohydrate-rich foods b. Watch bothersome foods F. Gastroesophageal Reflux (Figure H3-4) 1. Causes a. Eating or drinking too much b. Tight clothing c. Changes in position d. Medications and smoking e. Obesity f. Sphincter defect 2. Indigestion 3. Treatment and complications G. Ulcers 1. Peptic ulcers can be gastric or duodenal 2. Strategies a. Take prescribed medicine b. Avoid caffeine- and alcohol-containing foods c. Minimize aspirin and ibuprofen use d. No smoking Case Study 3: Managing GI Discomfort5 Mary Treat is a 68-year-old woman in reasonably good health. She is 64 inches tall and weighs 180 pounds. She takes a daily multi-vitamin supplement and over-the-counter antacids for heartburn. Her usual diet includes lean meat, chicken, fish, and fresh vegetables and seasonal fruit from her garden She now reports having severe heartburn after a family reunion picnic over the Labor Day weekend and over the past two days has experienced diarrhea and painful stomach cramps. 1. Based on her history, name at least two reasonable explanations for Mary’s sudden onset of diarrhea and cramps. 2. What may explain Mary’s symptoms of heartburn? 3. If food poisoning is suspected, how might this be related to Mary’s regular use of antacids? 4. What immediate treatment would you suggest for her current symptoms? 5. What information and advice would you offer Mrs. Treat to help her avoid this type of gastrointestinal discomfort in the future? 6. At what point would you advise her to seek medical care? Answer Key 1. See Highlight 3. Answers may include food poisoning or other infections or a sudden change in diet. 2. Overweight; eating or drinking more than usual at the family reunion; sudden change to a high-fat diet. 3. The strong acidity of the stomach that helps prevent bacterial growth is reduced with acid-blocking drugs; acid-blocking drugs can weaken the mucous barrier of the GI tract, increasing the risk for food-borne illness. 4. Avoid foods suspected of causing the diarrhea. Rest and drink fluids to replace losses caused by diarrhea; eat slowly, chew food thoroughly, and eat smaller meals. 5. Sudden dietary changes can “upset digestion” and should be made gradually. Avoid sudden changes in your diet. Eat in a relaxed manner. Don’t over-eat fat. Chew food well and take time to eat in a relaxed manner. Continue to eat a balanced diet that is low in fat even when traveling. Be prudent regarding use of acid-blocking drugs. Practice safe food handling to avoid foodborne illness. 6. If she experiences persistent diarrhea, heartburn, or other symptoms. Suggested Classroom Activities The study of digestion and absorption requires learning an immense number of new terms. With beginning students, it helps to introduce the digestive tract systematically, using a chart or DVD, and naming each part in sequence; then to use all the names and continue using the chart while explaining the processes of digestion and absorption. Warn students frankly that the task of learning the digestive system parts and their function is unglamorous but essential. To bring the subject to life, digress at intervals to share related knowledge they find intrinsically interesting, about choking, ulcers, and other topics. Classroom Activity 3-1: Obtaining Feedback From Students Objective: Cultivating/maintaining a positive learning environment Class size: Any Materials needed: 1 index card (3” x 5”) per student Instructions: Obtaining feedback from students is an excellent way to monitor their progress and respond to their needs. It only takes about 5 minutes of classroom time. Distribute 3 x 5 index cards—one per student. Instruct them to write on one side of the card “What’s going well in class,” and on the other side, “What could be better.” The feedback is usually valuable. Sometimes you can respond to distracting issues easily by adjusting classroom temperature or outside noise levels. The process communicates that you care enough to ask for feedback. Classroom Activity 3-2: Demonstration of the Digestive System Key concept: Visual of size of digestive tract Class size: Any Materials needed: 10-foot rope, hose or tube; small bag Instructions: Coil a 10-foot rope, hose, or tube in a small bag. Pull the rope out of the bag and instruct the students to guess how long the small intestine is. Have the students pass the rope down the rows of the classroom until the full rope is exposed. Classroom Activity 3-3: “Who Wants to Be a Millionaire?” as a Tool for Review (and Fun)6 Key concept: Review (at instructor’s discretion) Class size: Any Purpose: To review material, motivate students to study, and have fun. Materials needed: Computer projection system; Microsoft PowerPoint with animation and sound effects, plus review questions on PowerPoint slides; overhead projector; chair and table; index cards; hat or jar Setup: A computer projection system is used for the questions and an overhead projector for the point scale. The room is set up with a chair facing a table, which faces the projection screen. The student selected to play sits in the chair and has the three lifelines taped to the edge of the table. Once a student uses that lifeline, it is flipped over. How To Play: Selection of the student to play begins with the “fast finger” round. Every student receives an index card. The question may relate specifically to the subject matter or may be something like university trivia. The question is shown on the screen and the students have approximately 10-20 seconds to write down their answer. The correct answer is shown and every student who answers correctly puts the index card in a hat or jar. One name is then randomly selected to play. The play then follows the format of the television game. The lifelines are Ask the Audience (take a class vote on the possible answers), 50/50 (take away two of the wrong answers), and Phone a Friend (ask anyone in the classroom). The point scale (see sample) shows the levels of bonus points to be added to the upcoming exam. If a student becomes a millionaire, he or she receives 100 points (the value of the test). Student Reaction: Student comments have been very positive. It helps them review material and they have really enjoyed the game and the effort put into its construction. There is a lot of encouragement from the class for the student player. A few students in different semesters became “Millionaires” and the class cheered for them! Comments: Although the initial construction was quite time consuming, once a set is done with the animation and sound effects, the file can be copied and new questions substituted. Points Scale: $1,000,000 100 pts. $4,000 7 pts. 500,000 25 pts. 2,000 6 pts. 250,000 20 pts. 1,000 5 pts. 125,000 15 pts. 500 4 pts. 64,000 12 pts. 300 3 pts. 32,000 10 pts. 200 2 pts. 16,000 9 pts. 100 1 pts. 8,000 8 pts. Classroom Activity 3-4: Evaluation of Products for Digestive Problems Key concept: Digestive problems Class size: Any Instructions: Have students bring over-the-counter products designed to treat common digestive problems (heartburn, constipation, diarrhea, hemorrhoids). Discuss the appropriate and inappropriate uses of these medications and adverse health implications associated with misuse and overuse of certain medications. For example, overuse of medications for heartburn may foster a basic environment in the stomach and therefore hinder iron absorption. Present alternative solutions to these common digestive problems as presented in Highlight 3. Study Card 3 Answer Key 1. Since the mouth is the entry point for both foods and air, the epiglottis must cover the trachea as part of the swallowing reflex so that swallowing and breathing don’t interfere with each other. The muscular diaphragm necessary for breathing separates the mouth from the stomach, so the esophagus must conduct small quantities of food through it. To allow time for enzymatic digestion and absorption of nutrients, food must move slowly but steadily at a pace that permits all reactions to reach completion; the processes of peristalsis and segmentation, accomplished by layers of longitudinal and circular muscles, provide this movement. Foods must be pulverized into tiny pieces and lubricated with fluids to allow enzymes to work and the food to move along; the powerful action of multi-layered stomach muscles puree the food, and secretions from the GI tract and accessory organs supply the fluids. Later, most of these fluids need to be reabsorbed to prevent excess water loss and produce a stool consistency appropriate for periodic elimination, and the large intestine does this, as well as provide a holding chamber where stool can collect until time for excretion. 2. Organs that secrete digestive juices include the mouth (saliva from salivary glands), stomach (gastric juice from gastric glands), pancreas (pancreatic juice), small intestine (digestive enzymes produced by enterocytes), and liver (bile). The fluids in these digestive juices lubricate the food and provide a medium into which food particles can dissolve as the food is broken up by the GI tract’s muscular action—thus aiding mechanical digestion. The enzymes chemically break apart the food into nutrient compounds small enough to be absorbed. 3. c 4. c 5. a 6. d 7. b 8. a 9. c 10. b 11. d 12. Enzyme activity changes proportionately in response to the amounts of carbohydrate, fat, and protein in the diet. If a person has been eating mostly carbohydrates, the pancreas makes and secretes mostly carbohydrases; if the person’s diet has been high in fat, the pancreas produces more lipases; and so forth. Fat and protein take longer to digest than carbohydrate does. Cholecystokinin, released in response to fat or protein in the small intestine, slows GI tract motility, helping to maintain a pace that allows all reactions to reach completion. 13. To help the GI tract function optimally, you should maintain cardiovascular health, get adequate sleep, engage in regular physical activity, manage stress, eat at a relaxed pace in a pleasant atmosphere, and consume a healthful diet that exemplifies the principles of balance, moderation, variety, and adequacy. 14. c 15. c Critical Thinking Questions7 1. Identify and discuss potential factors related to the oral cavity that may impede the process of digestion of food. What dietary changes would facilitate food intake for those with oral cavity problems? 2. Discuss how the pH environment of the various portions of the digestive tract facilitates the process of enzymatic digestion. 3. Provide an example of how certain nutrients can enhance the absorption of others. How does this relate to nutrient bioavailability? If the absorption of certain nutrients can be enhanced through the presence of other nutrients or foods, how does this affect the concept of food combining? 4. What is the difference between probiotics and prebiotics in regard to gastrointestinal tract function? What benefits does a synbiotic provide in the body? 5. Explain the concept of a negative feedback mechanism as it relates to gastric acid secretion. 6. How does the pancreas regulate digestive enzymes in order to promote intestinal health and well-being? Answer Key 1. The digestive process begins in the mouth or oral cavity. If an individual has dental problems, this may affect the ability to chew foods. Thus, the mechanical digestive process will be hampered, leading to the possibility of the individual choking and/or potential aspiration. Individuals who have alterations in taste due to medication effects, as a result of oral infections, and/or as a result of smoking may be less likely to eat certain foods. Individuals who have oral infections as a result of dental disease and/or systemic disease may not be able to take foods by mouth as this can be associated with pain. Additionally, if the infectious process affects other structures such as the pharynx and throat, swallowing may be further impaired. In order to facilitate food intake in the context of oral cavity problems, one could implement an altered-consistency therapeutic diet. Dependent on the particular problem, one could offer a clear liquid or full liquid diet. As these are not considered to be a nutritionally complete, they can be used only for a short period of time. A mechanical soft diet is a nutritionally complete diet that could be used long term. Additionally, thickened liquid diets can be utilized if an individual is at risk for aspiration. 2. The alimentary pathway utilizes a complex system of different biochemical secretions to facilitate the process of digestion. The structural organs of the alimentary tract have their own acid-base environments that allow for specific enzymes to act. For example, the stomach is highly acidic. Not only is this low pH the ideal environment for the activity of gastric proteases, but it uncoils food proteins, exposing them to these enzymes. Similarly, the pH environment of the small intestine, which is alkaline, is well suited to pancreatic enzyme action. As the majority of nutrient digestion and absorption occurs in the small intestine, it is critical that this alkaline medium be maintained. Alterations in the pH environment of the small intestine would cause serious malabsorption effects. To mediate the pH environment of the small intestine, bicarbonate is released in pancreatic juice to neutralize the HCl entering with the chyme from the stomach. 3. The ingestion of vitamin C (ascorbic acid) taken in conjunction with foods that are high in nonheme iron can lead to increased iron absorption. Iron as a mineral is more readily available in heme food sources (animal proteins). Vitamin C enhances the absorption of nonheme iron from both animal and plant food sources, thus increasing its bioavailability. Foods taken in combination, as in the case of complementary proteins, can lead to increased bioavailability of essential amino acids. Foods in meals are typically not eaten in isolation but as a component of food combining. As noted in the textbook, the concept of “food combining” is based on the notion that separation of food items, specifically protein sources, improves absorption. Clinical evidence suggests that there is no scientific basis for promotion of this concept. Available literature provides few (if any) scientific studies that are of sufficient rigor. The premise of this dietary pattern relates more to digestive issues. Stressed dietary patterns sequence foods (take a layered approach) based on the digestive system’s capabilities to digest them. Based on the premise of food combining, the separation of foods will allow for individual digestive action. 4. Probiotics are considered to be an important preventative health factor in maintaining healthy function of the gastrointestinal tract. They are marketed by companies based on their ability to regulate normal bowel function and prevent constipation and irregularity. Additionally, they are marketed as being effective against other health conditions such as lactose intolerance and inflammatory bowel disease and as enhancing immune function. Probiotics are used in the manufacture of yogurt and marketed as such in the American diet. Component parts of prebiotics are dietary plant fibers that are not digested in the body. Prebiotics work in the body to promote bacterial growth, which in turn helps to produce the fat-soluble vitamins D and K. A food product that is defined as a synbiotic contains both probiotic and prebiotic sources. The inclusion of both of these substances provides increased viability within the digestive tract so that functionality can be maintained. Characteristics of synbiotic food products include antimicrobial, anticarcinogenic, antidiarrheal, and antiallergenic properties. They may be beneficial in osteoporosis prevention, reduction of serum lipids and blood sugar, regulation of the immune system, and relief of liver-related brain dysfunction (http://www.innvista.com/health/nutrition/biotics/synbiot.htm). 5. A negative feedback mechanism involves a threshold response to an established baseline to increase secretion of an identified substance with a desired effect. Once the desired effect has been reached, then the secretion of the identified substance will stop. In the presence of food in the stomach, gastrin is released, leading to an increased release of hydrochloric acid. Once the pH of the stomach environment is sustained at 1.5 (a highly acidic pH), gastrin secretion is stopped. Thus, through negative feedback the desired acidity has been achieved but not exceeded. There is no longer a need for gastrin release as there is sufficient hydrochloric acid to maintain a strong acidic environment. 6. The pancreas utilizes two methods to help regulate the actions of digestive enzymes. The first method is based on dietary composition: the production of specific digestive enzymes is based on dietary intake. If a person eats proportionally more carbohydrates, then more carbohydrases are secreted. The second method whereby the pancreas helps to regulate digestive enzymes is to secrete inactive forms of enzymes. These inactive enzyme forms will then require a chemical activation process in order to become active. IM Worksheet Answer Key Worksheet 3-1: Chapter 3 Crossword Puzzle 1. mouth 2. homeostasis 3. probiotics 4. constipation 5. sphincters 6. lymph system 7. enzymes 8. microvilli 9. digestion 10. celiac disease 11. liver 12. peristalsis Worksheet 3-2: Digestion, Absorption, & Transport—DAT For digestion/enzyme activation and absorption columns, see Figure 3-7. Transport: proteins, small lipids, water-soluble vitamins, minerals, and water are released directly into the bloodstream, whereas larger lipids and fat-soluble vitamins are first released into the lymphatic system. Hormonal regulation: cholecystokinin for lipids and proteins. 1. Nutrients and other food components can enhance or inhibit absorption of other nutrients ingested at the same time; e.g., vitamin C in orange juice can increase absorption of iron from bread when they are consumed at the same meal 2. Health/strength of GI tract muscles (motility), damage to tissues of the GI tract due to disease or injury Worksheet 3-3: Food Habits, Digestion, and Absorption 1. Promote: a, b, e, h; Impede: c, d, f, g, i 2. Answers will vary 3. Answers will vary; see Table H3-1 for examples of positive eating habits Worksheet 3-4: Further Exploration on Digestion (Internet Exercise) 1. b, c, d, e, a 2. b 3. b 4. b, c, d 5. a 6. b 7. a 8. a 9. a 10. b Worksheet 3-1: Chapter 3 Crossword Puzzle 1   2   3 4                                     5 6         7       8                         9             10                                                 11                 12                             Across Down 4. Eating high-fiber foods and drinking plenty of fluids can help alleviate _____. 7. Proteins that are essential for breaking down foods chemically 10. Involves an autoimmune response to gluten in foods 11. Body organ that detoxifies harmful substances that are ingested 12. Contractions in GI tract muscles that move food through the digestion process 1. Location where the process of digestion begins 2. Refers to the body’s overall plan to keep things “relatively the same” 3. Bacteria that are beneficial to the human body 5. Muscles that control the flow of food throughout the GI tract 6. Fat-soluble nutrients are absorbed into the _____. 8. Microscopic hairs that cover the intestinal villi and are used to absorb nutrients 9. How food is broken down into nutrients for absorption Worksheet 3-2: Digestion, Absorption, & Transport—DAT For each of the nutrients listed below, indicate the mechanism of action for each of the processes identified above. Nutrient Digestion/Enzyme Activation Absorption Transport Hormonal Regulation Carbohydrates Mouth → salivary amylase Stomach → no active process Small intestine → pancreatic amylase Large intestine → fiber action Primary site = small intestine, via active transport Directly into the bloodstream Insulin, glucagon Lipids Proteins Vitamins Minerals Water 1. What dietary factors not listed above influence the processes of DAT? 2. What structural factors not listed above influence the processes of DAT? Worksheet 3-3: Food Habits, Digestion, and Absorption Digestion transforms the foods we eat into nutrients and absorption moves nutrients from the GI tract into the blood. Optimal digestion and absorption depend on the good health of the digestive tract, which is affected by such lifestyle factors as sleep, physical activity, state of mind, and the meals you eat. 1. Identify which of these foods and food habits promote or impede healthy digestion and absorption. Foods and Food Habits Promote Impede a. Take small bites of food. b. Chew thoroughly before swallowing. c. Exercise immediately after eating to prevent weight gain. d. Eat a low-fiber diet. e. Drink plenty of fluids. f. Eat a few large meals instead of several smaller ones. g. Eat quickly and then lie down to rest. h. Create a meal using citrus fruits and meat. i. Tackle family problems at the dinner table. 2. Do you experience GI distress regularly? 3. What changes can you make in your eating habits to promote GI health? Worksheet 3-4: Further Exploration on Digestion (Internet Exercise) Go to this website to answer questions 1-10: http://digestive.niddk.nih.gov/ddiseases/pubs/yrdd/. 1. Arrange the organs that make up the digestive system in sequential order starting from the mouth. a. anus b. esophagus c. stomach d. small intestine e. colon 2. The liver and the stomach are considered to be "solid" digestive organs. a. True b. False 3. The lower esophageal sphincter closes the passage between the stomach and the pancreas. a. True b. False 4. Which of the following statements regarding factors affecting emptying of the stomach is/are true? Select all that apply. a. Carbohydrates spend the longest amount of time in the stomach. b. The type of food eaten affects the stomach emptying rate. c. The degree of muscle action of the small intestine affects stomach emptying. d. Fats remain in the stomach for the longest time period. 5. Starches are digested in a two-step process, whereas sugars are digested in a one-step process. a. True b. False 6. Insoluble fiber takes on a gel-like texture in the intestines, making it easier to facilitate elimination. a. True b. False 7. Protein digestion begins in the stomach. a. True b. False 8. Bile acids combine with cholesterol and fatty acids to help fat molecules move into the cells of the mucosa. a. True b. False 9. Which of the following hormones regulate appetite? a. Ghrelin and peptide YY b. Gastrin and peptide YY c. Secretin, CCK, and gastrin d. Secretin and ghrelin 10. Intrinsic nerves release acetylcholine and adrenaline. a. True b. False Handout 3-1: Peristalsis and Segmentation Handout 3-2: Examples of Hormonal Feedback Loops Contributed by Carrie King.↩ Worksheets 3-2 and 3-4 contributed by Daryle Wane.↩ Worksheet 3-3 and Handouts 3-1, 3-2, 3-3, and 3-4 contributed by Sharon Rady Rolfes↩ Contributed by Melissa Langone.↩ Contributed by Barbara Quinn.↩ Activity provided by: Dr. Inza Fort and Dr. Ro Di Brezzo, University of Arkansas↩ Contributed by Daryle Wane.↩