1. Answers to review sheet
Digestive Review
Answers to review sheet

2. The principal structure of the digestive system is an irregular tube, open at both ends, called the _alimentary___ canal or the _gastrointestinal tract.

3. 2. Food is broken down physically, called _mastication___ and chemically called __digestion_______.

4. 3. Chemical digestion results from the action of digestive enzymes
3. Chemical digestion results from the action of digestive enzymes. The first enzyme, _amylase_____, found in saliva, breaks down carbohydrates. An antibacterial enzyme called _lysozyme____ is also found in saliva.

5. The enzyme _pepsinogen or pepsin_ is excreted by the stomach and begins the chemical digestion of proteins.

6. The three salivary glands are the _parotid________, _sublingual__ and the _submandibular______.

7. The inside, hollow space within the digestive tract is the _lumen_______.

8. 7. The inner layer of the intestinal tract is called the _mucosa_____
7. The inner layer of the intestinal tract is called the _mucosa_____. It secretes _mucus______ to allow food to move easily through.

9. 8. The second layer, the _submucosa__, is connective tissue that contains blood vessels, nerves and lymphatic vessels.

10. The 2-3 layers of muscle is called the _muscularis____.

11. The outermost covering or coat of the digestive tube is the _serosa____.

12. The wavelike, rhythmic contraction of the muscular coat, called _peristalsis moves food through the digestive system.

13. Another name for the throat is the __pharynx___.

14. The muscular, mucus-lined tube that connects the throat to the stomach is the _esophagus_________.

15. The _stretch_____ reflex brought on by food entering the stomach, signals the release of hormones that in turn release more enzymes.

16. After food leaves the mouth and enters the esophagus, it is called a bolus____.

17. 16. The opening from the esophagus to the stomach is the _cardiac________ sphincter.

18. 17. When stomach contents go back onto the esophagus two or more times a week, it is called __GERD, acid reflux (gastroesophageal reflux disease) or heartburn.

19. 18. Contraction of the stomach’s muscular walls mixes the food thoroughly with the gastric juice and breaks it down into a semisolid mixture called _chyme_______.

20. 19. The acidic gastric juice secreted by the cells of the stomach is _hydrochloric acid___. It has a pH of approximately __2___.

21. 20. The circular muscle that releases food from the stomach to the duodenum is the _pyloric________ __sphincter__.

22. 21. The small intestine is approximately __22__ feet or 6. 5 meters
21. The small intestine is approximately __22__ feet or 6.5 meters. The surface area is about _2000___ square feet.

23. 22. The three parts of the small intestine are _duodenum_____, __jejunum________ and _Ileum__________.

24. 23. The folds of the small intestine are covered in small finger-like projections called _villi____, which are covered in even smaller projections called ___micro______ _villi___.

25. Each villus in the intestine contains a lymphatic vessel or _lacteal___ that absorbs lipid or fat materials from the chyme passing through the small intestine.

26. 25. Most of the chemical digestion occurs in the first part of the small intestine, called the _duodenum______.

27. 26. Bile is created by the _liver_______ and stored in the _gall__ _bladder__

28. 27. Bile is drained out of the liver by the _hepatic___ ducts.

29. 28.Bile contains salts that __emulsify__ or break down fats.

30. 29. When chyme containing lipid or fat enters the duodenum, it initiates a trigger for the hormone CCK, _cholecystokinin_, which stimulates the contraction of the _gall bladder_____ to release bile into the duodenum.

31. 30. Solid clumps of material (mostly cholesterol) that form in the gallbladder only cause problems when they block a duct are called __gallstone______.

32. 31. The pancreas works as an _exocrine_____ gland when it secretes digestive enzymes and an __endocrine____ gland when it secretes hormones.

33. 32. The pancreatic juices are the most important because there are enzymes to break down all three major kinds of foods: _carbohydrates____, _lipids__, and __proteins____.

34. 33. Pancreatic juices empty into this part of the small intestine: _duodenum______

35. 34. The large intestine is approximately 1
34. The large intestine is approximately 1.5 meters or _5__ feet in length.

36. 35. It is called the large intestine because it is larger in _diameter____ than the small intestine.

37. 36. The small intestine empties into the large intestine through the __ileocecal______ valve. The name makes sense because the unabsorbed food moves from the _ileum_______ of the small intestine to the _cecum__ of the large intestine.

38. During its movement through the large intestine, material that escaped digestion in the small intestine is acted on by this single celled organism: _bacteria_____

39. These single celled organisms are responsible for the synthesis of Vitamin __K_, which is important for normal blood _clotting____.

40. The percentage of nutrients absorbed by the small intestine: __95%____.

41. 41. If enough water is not absorbed by the large intestine, _diarrhea_____ results. If too much water is absorbed, then __constipation_______ can result.

42. The subdivisions of the large intestine listed in order are:
__cecum_______________
__ascending colon_____
__transverse colon_____
___descending colon__
___sigmoid colon_______
___rectum______________
____anal canal_________

43. 43. This vestigial organ can rupture sending bacteria into the abdominal cavity: ___appendix_______________

44. This connective tissue extensions between and around the digestive organs in the abdomen provide blood supply, insulation and anchors the small intestine to the abdominal wall: _mesentary__________.

45. The four major types of teeth are the __incisors____, __canines_____, __premolars______ and the __molars__________.

46. 45. The portion of the tooth that is exposed and visible in the mouth is the __crown________

47. 46. The tooth _root_____ fits into the socket of the upper or lower jaw.

48. 47. A fibrous _periodontal_________ membrane lines each tooth socket.

49. 48. Another name for the gums is the __gingiva_______, thus the name of a gum infection is gingivitis.

50. 49. Even though animals could not live without bacteria in the digestive system, sometimes a bad bacteria can get in and cause problems. H. pylori can cause holes in the stomach walls called _ulcers_____,

51. 50. Many people can not digest milk sugars and get gastric distress
50. Many people can not digest milk sugars and get gastric distress. These people are _lactose_____ intolerant.

52. People over 50 years of age should be checked for colon cancer through this procedure: __colonoscopy_______.

53. Another name for the formation and removal of feces: __defecation____.

54. The largest gland/internal organ is the __liver____________.

55. 54. This holds the tongue to the floor of the mouth: _lingual_frenelum_.

56. 55. The main cause of gall stone is consuming too much _fat______.

57. 56. The flap of cartilage that directs food to the esophagus and not the trachea is the _epliglotis____.

58. 57. Pouches of infection that form in the wall of the colon is called _diverticullitis_______________. This condition can be prevented by water, exercise and a high __fiber________ diet.

59. 58. When an internal body part pushes into an area where it doesn’t belong, it is called a __hernia___________. Hiatal hernias are found at the base of the _esophagus______________ where it leads into the stomach.

60. Flossing your teeth can prevent heart disease and this dental gum disease: ___periodontal________________ disease.

61. Fruits and vegetables contain a high amount of __water___________, so they have a lot of volume, but not a lot of calories.