2. What parts of the mouth contribute to the formation of the bolus? What role does each mouth part contribute?

Transcription

1 BIOLOGY 12: CHAPTER 12 - REVIEW WORKSHEET DIGESTIVE SYSTEM A. CHAPTER REVIEW 1. List and explain the four functional stages of digestion. 2. What parts of the mouth contribute to the formation of the bolus? What role does each mouth part contribute? 3. What prevents food from entering the nasal chamber (nasopharynx) and the trachea during swallowing of food? 4. What enzymatic reaction occurs in the mouth? 5. The opening to the larynx is called the, which is covered when the trachea moves up under the. 6. a) List the four layers of the digestive tract and explain the functions of each. b) Label the layers in the diagram. 1

2 7. What causes the food to be pushed along in the esophagus? 8. What is responsible for heartburn and how is it normally prevented? 9. List the functions of the stomach. What is chyme? 10. What is an ulcer and why does it form? 11. Write the chemical reaction that occurs in the stomach. 12. List the functions of the small intestine. What molecule from the pancreas neutralizes the acidity of chime? 13. What five reactions take place in the duodenum? 14. Describe the structure of villi and microvilli in the small intestine. 15. What three enzymatic reactions take place in the small intestine? 16. How are the small nutrient monomers absorbed across the wall of each villus? What do they enter? 17. What is the function of the large intestine? How does its size compare with the small intestine? 18. a) Which associate organ of the large intestine plays a role in immunity? b) What is the term used to refer to the inflammation of this organ? c) What is the term used to refer to surgical removal of this organ? 19. Over 99% of bacteria in the colon are classified as, because they die in the presence of oxygen. 20. Describe the effects of bacteria in the large intestine. What does a HIGH coliform count in lake water mean? 21. How do food poisoning and nerve stimulation cause diarrhea? Why is this dangerous to a person s health? 22. How does mineral oil work to overcome constipation? 2

3 23. What is the exocrine function of the pancreas? Name the transport vessel of pancreatic secretions. 24. What is the endocrine function of the pancreas? How do these feedback cycles work? 25. What are the components of bile? Where is bile produced? Where is it stored? 26. Explain why the liver is said to act as the gatekeeper of the blood. 27. Define deamination. What happens to the amino groups in the liver? How is it excreted? Write out the reaction of urea production. 28. Explain ALL the functions of the liver. 29. Read p Distinguish between haemolytic jaundice and obstructive jaundice. 30. What are the causes of the various forms of viral hepatitis? 31. What is lactose intolerance due to? What are the consequences of drinking milk in these individuals? (refer to p. 224) 32. Define a nutrient. How is a balanced diet achieved? 33. Define an essential amino acid. Distinguish between a complete and incomplete protein source. 34. Why are simple carbohydrates sometimes referred to as empty calories? (p. 227) 35. What are the advantages of both insoluble and soluble fibre in our diets? (p. 227) 3

4 36. List four ways to reduce dietary fat. 37. Distinguish between the functions of low-density lipoproteins and high-density lipoproteins. 38. What are vitamins? Give their function. 39. How do free radicals harm the body? (p. 230) 40. How does the body defend itself against free radicals? 41. Read p What is the cause of osteoporosis? What three things can women do to reduce the risk of developing osteoporosis? B. COMPLETION AND SHORT ANSWER QUESTIONS 1. The stomach is directly connected to the above and the (2 words) below. 2. The major food molecule digested in the stomach is, which is hydrolyzed by the enzyme. The enzyme s inactive form is called. 3. Among its chemical aspects, every digestive enzyme has a preferred. 4. Before fats are digested by the enzyme, they are first emulsified by. 5. Pancreatic juices enter the small intestine (duodenum) by way of the duct and contain for the digestion of EVERY type of food. 6. The liver first receives the products of digestion by means of the vein; any excess glucose is stored as. 7. The secretion of digestive juices is controlled generally by both and. 8. Surface area in the small intestine is increased greatly by the presence of and. 9. There are essential amino acids required by adults. 10. There are essential fatty acids required by adults. 11. Complete the following table. HORMONE PRODUCTION SITE TRIGGER/CAUSE OF RELEASE AFFECTED ORGAN(S) ACTION OF AFFECTED GASTRIN ORGAN GASTRIC INHIBITORY PEPTIDE (GIP) SECRETIN CHOLECYSTOLKININ (CCK) 4

5 12. Vitamins are portions of, which are necessary for cellular metabolism. 13. Answer the following questions about the digestive tract. a) In which part of the digestive tract are nutrient molecules absorbed? b) The absorbed nutrient molecules enter what vein associated with the liver and intestine? c) In which specific part of the digestive tract does pancreatic juice enter? d) In which specific part of the digestive tract does bile enter? e) The three accessory organs that do NOT contain food are the,, and. f) What parts of the digestive tract do NOT have ducts entering them and do NOT secrete digestive juices? 14. Carbohydrate Digestion (starch) Starch digestion begins in the, Here, the ducts empty saliva from the glands. There are three pairs of these glands, named parotid glands, sublingual glands, and submandibular glands. The saliva from these glands contains the enzyme, and this enzyme breaks down starch to the disaccharide. Starch will continue to be broken down in the. Here, a duct empties from the. Pancreatic juice contains the enzyme, which breaks down starch to the disaccharide. Starch digestion is completed when this disaccharide is broken down to, a monosaccharide that can be absorbed by intestinal. The enzyme that converts maltose to glucose is called, and this enzyme is secreted by epithelial cells of the intestinal villus. 15. Protein Digestion (meat) Protein digestion begins in the. The glands line the wall of the stomach. They secrete the enzyme, which is converted into its active form by hydrochloric acid; this enzyme breaks down protein into. In the (gland), another enzyme called acts on protein in the, breaking down protein into. Protein digestion is completed when peptides are broken down to, molecules small enough to be absorbed by intestinal villi. This is achieved by the enzyme, which is produced by the epithelial cells of the intestinal villus. 16. Fat Digestion (butter) Fat is first emulsified by, a substance made by the liver and stored in the (gland). The secretions in this gland enter the small intestine by way of the duct. After the fat has been emulsified, it is broken down by the enzyme, which is found in pancreatic juice. Fats are broken down to and fatty acids, molecules small enough to be absorbed by intestinal villi. After resynthesis (~repackage) into, fats enter the, which are part of the lymphatic system. 17. Path of Food. a) Food consists of the large organic molecules,, and. In the mouth, the only type of food digested are. The mouth has a neutral of. The food passes down the long tube called the. A rhythmic contraction called pushes the food along. 5

6 b) After passing through a sphincter (circular muscle), the food enters the. Here the primary food acted on is. This organ has a(n) ph of. The food is now called, which passes through another sphincter into the, which is the first section of the. c) Two ducts enter this organ; they are the from the and the from the. Bile contains an emulsifier that divides fat into fat droplets. Pancreatic juice contains enzymes that act on,, and. Lining the walls of the intestine are with on the apical surface of each cell. The epithelial cells produce enzymes that finish digestion by converting to glucose and to amino acids. Thus the small nutrient molecules that are absorbed by villi are and, which enter the portal vein. and enter the. d) The portal vein takes the nutrients to the, an organ of homeostasis. For example, this organ stores glucose as, and always keeps the blood glucose level constant. This organ can also remove amino groups from and convert the amino groups to, a nitrogenous waste product. 18. What happens to a person who takes in more calories/energy than needed? C. DIGESTIVE ENZYME ACTIVITY For each combination of substances below, decide whether digestion will or won t occur. If it does not, provide a reason why. (Hint: remember to consider optimum ph of the enzyme) 1. trypsin, NaHCO3, egg white - warm gently 2. salivary amylase, water, egg white warm gently 3. pepsin, HCl, egg white freeze 4. pancreatic amylase, HCl, starch heat to boiling 5. lipase, NaHCO3, fats warm gently 6. maltase, HCl, maltose warm gently 7. peptidases, fat, HCl warm gently 8. pepsin, HCl, egg white warm gently 9. trypsin, starch, water warm gently 10. HCl, egg white, water, warm gently 6