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2010-10-14 13:18:33

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  1. What are the four functions of the digestive system?
    • Take in food,
    • Break it down into nutrient molecules,
    • Absorb nutrients into the bloodstream,
    • Excrete indigestible remains and metabolic products.
  2. What is the continuous, muscular tube, about 20 to 25 ft. long that digests food and absorbs through its lining into the blood?
    Alimentary canal, GI, or gut
  3. Name the 6 structures that make up the alimentary canal.
    • Mouth
    • Pharynx
    • Esophagus
    • Stomach
    • Small intestine
    • Large intestine
  4. What type of organs produce a variety of secretions that assist in the breakdown of food?
    Accessory digestive organs
  5. Name 4 accessory digestive organs.
    • Teeth
    • Tongue
    • Gallbladder
    • Large digestive glands (salivary glands, liver, pancreas)
  6. What are the 6 digestive processes?
    • Ingestion
    • Propulsion
    • Mechanical digestion
    • Chemical digestion
    • Absorption
    • Defecation
  7. This is the elimination of indigestible substances via the anus in the form of feces.
  8. This is taking food into the digestive tract, usually via the mouth.
  9. This is the movement of products into the blood or lymph.
  10. What is the major absorption site?
    Small intestine
  11. This is the process of moving food into the next organ.
  12. What is the process in which food is broken down by enzymes?
    Chemical digestion
  13. Where does chemical digestion begin? Where is it completed?
    • Mouth
    • Small intestine
  14. This is the process by which food is prepared for chemical digestion.
    Mechanical digestion
  15. What are 5 things included in mechanical digestion?
    • Chewing
    • Mixing of food with saliva by the tongue,
    • Churning food in the stomach,
    • Segmentation,
    • Mixing digestive juices
  16. The abdominal aorta supplies which 5 organs of the digestive system?
    • Spleen
    • Liver
    • Stomach
    • Small intestine
    • Large intestine
  17. This circulation collects nutrient-rich venous blood draining from the digestive viscera and delivers it to the liver.
    Hepatic portal circulation
  18. What organ uses the nutrients for metabolic processing or for storage before releasing them to the blood stream for general cellular use?
  19. The walls of the alimentary canal have what four basic layers?
    • Mucosa
    • Submucosa
    • Muscularis externa
    • Serosa
  20. What is the outermost layer of the alimentary canal wall?
  21. The serosa is a single layer of what type of cell?
    Squamous epithelial
  22. What layer of the alimentary canal wall is responsible for segmentation and peristalsis?
    • Muscularis externa
    • The muscularis externa may thicken forming these in several places along the tract. They control food passage.
    • Sphincters
  23. What is the innermost layer of the alimentary canal?
    Mucosa or mucous membrane
  24. The mucosa is involved in what three functions?
    • Secretion
    • Absorption
    • Protection against infectious disease
  25. What layer of the alimentary canal wall enables the stomach to regain its normal shape after storing a large meal due to the presence of elastic fibers?
  26. What layer of the alimentary canal is composed of dense connective tissue containing blood and lympatic vessels, lymphoid follicle, and nerve fibers?
  27. What is another name for the mouth or oral cavity?
    Buccal cavity
  28. Organ which provides movement and aids in swallowing?
  29. This provides a rough surface and a forward motion for swallowing food.
  30. These secrete saliva.
    Salivary glands
  31. Enzymes begin the chemical breakdown of what type foods?
    Starchy foods
  32. What are the 4 functions of saliva?
    • Cleanse the mouth
    • Dissolve food chemicals so they can be tasted
    • Moisten food
    • Aids in compacting food into a bolus
  33. What percentage of saliva is water?
    97 to 99.5%
  34. What is the pH of saliva?
    6.75 to 7 (slightly acidic)
  35. What type of antibody can be found in saliva?
  36. What digestive enzyme can be found in saliva?
  37. These tear and grind food, breaking down into smaller fragment.
  38. Teeth lie in sockets in the gum covered margins of what bones?
    • Mandible
    • Maxilla
  39. The sockets that teeth lie in are also known as what?
  40. The side to side movement and the opening and closing of jaws along with the use of the tongue to move food between teeth is what?
    Chewing or mastication
  41. What is the dental formula for permanent teeth?
    2, 1, 2, 3 (incisors, canines, premolars, molars)
  42. What is the dental formula for deciduous teeth?
    2, 1, 2, 2
  43. From the mouth, food passes through which 2 common passageways for food, fluid, and air?
    • Oropharynx
    • Laryngopharynx
  44. The mucosa of the pharynx contains what type of friction-resistant epithelium?
    Stratified squamous
  45. The muscle layers of the pharynx propel food where?
  46. What is the length of the esophagus?
    25 cm (10 in)
  47. Is food routed posteriorly or anteriorly into the esophagus?
  48. At which point does food get routed into the esophagus?
    Epiglottis, larynx
  49. The epithelium of the esophagus secretes digestion enzymes and is composed of what type of cell?
    Simple columnar epithelium
  50. The esophagus joins the stomach here. It acts as a sphincter.
    Cardiac orifice
  51. This surrounds the sphincter at the cardiac orifice and helps keep it closed when food is not being swallowed.
    Muscular diaphragm
  52. The chemical breakdown of proteins occurs in what organ?
  53. Food is converted into this creamy paste in the stomach.
  54. The small intestine extends from this point in the epigastric region and ends at this valve.
    • Pyloric sphincter
    • Ileocecal
  55. What is the length of the small intestine?
    2 - 4m (7 - 13 ft)
  56. What are the 3 subdivisions of the small intestine?
    • Duodenum
    • Jejunum
    • Ileum
  57. What is the "empty" portion of the s. intestine that extends from the duodendum to the ileum? How long is it?
  58. Jujenum, 8 ft
  59. What is the "twisted" portion of the s. intestine that joins the l. intestine at the ileocecal valve? How long is it?
    Ileum, 12 ft
  60. What 2 subdivisions of the s. intestine hang in coils in the central and lower part of the abdominal cavity, suspended from the posterior abdominal wall?
    • Jejenum
    • Ileum
  61. What "tufts of hair" are fingerlike projections of the mucosa that have columnar epithelial cells?
  62. What is in the core of each villus?
    Dense capillary bed
  63. What are the tiny projections of the plasma membrane of the absorptive cells of the mucosa? The fuzzy appearance that it gives to the mucosal surface is called the brush border.
  64. What type of enzymes are needed for complete digestion of carbs and proteins?
    Brush border enzymes
  65. These are found in increased numbers at the end of the s. intestine and are involved in preventing bacteria from entering the bloodstream.
    Peyer's patches
  66. The intestinal glands produce how many L of juice daily?
  67. The distension or irritation of the intestinal mucosa by this stimulates intestinal juice production.
  68. Intestinal juice is isotonic with blood plasma with an alkaline level of what?
    pH 7.4 - 7.8
  69. What two structures secrete intestinal juice?
    • Duodenal glands
    • Goblet cells of the mucosa
  70. Bile is produced in what organ before being sent to the duodenum?
  71. Where is bile stored?
  72. What is a major function of bile?
    Aid in digestion - break up fats
  73. Name 4 things that can be found in bile.
    • Bile salts
    • Bile pigments
    • Cholesterol
    • Variety of electrolytes
  74. What component of bile is derived from cholesterol and emulsifies fats?
    Bile salts
  75. Emulsified fats are easily accessible to what fat-digesting enzymes?
  76. The bile pigment bilirubin is a waste product of the breakdown of what type of cells?
  77. Exposure of the intestinal cells to fatty chime releases this protein which stimulates the liver cells to secrete bile.
  78. Organ that is a thin-walled green muscular sac about 4 in long.
  79. The gallbladder concentrates bile by absorbing what?
    Water and ions
  80. What gland is encircled by the C-shaped duodenum and extends across the abdomen?
  81. What are the clusters of secretory cells within the pancreas?
  82. Enzymes produced in the pancreas end up where?
  83. The pancreas secretes these "fermenting" granules.
  84. The pancreatic islets house what three types of hormone secreting cells?
    • Alpha
    • Beta
    • Delta
  85. The hormone glucagon has what effect on blood sugar?
  86. The hormone insulin has what effect on blood sugar?
  87. What cells of the islets of Langerhans produce somatostatin (slows growth, works against pituitaries)?
  88. What cells of the islets produce insulin?
  89. What cells of the islets produce glucagon?
  90. In what organ are the islets of Langerhans located?
  91. What are the protein digesting enzymes that are produced and released as inactive?
  92. Pancreatic juice is clear, contains water and enzymes, and has a pH of what? How much is produced daily?
    • pH 8
    • 1200 - 1500 ml
  93. This activates carboxypeptidase and chymotrypsin.
  94. What pancreatic enzymes are secreted active break down carbs? Fats? Nucleic acid?
    • Amylase
    • Lipases
    • Nucleases
  95. Where does the large intestine begin and end?
    • Ileocecal valve
    • Anus
  96. What does the l. intestine absorb from indigestible food residues?
  97. This double layer of peritoneum is a sheet of two serous membranes fused back to back.
  98. What are three functions of the mesentry?
    • Provide routes for blood vessels, lymphatic, and nerves
    • Hold organs in place
    • Store fat
  99. These colonize the colon, metabolize proteins, and ferment indigestible carbs.
    Bacterial flora
  100. The bacterial flora in the GI system helps synthesize these 2 types of vitamins.
    • K - for blood clotting
    • B complex - B12
  101. What is the peaceful coexistence of bacteria and host?
  102. What initiates the defecation reflex?
    Stretching of the rectal wall
  103. Is the initial reflex sympathetic or parasympathetic?
  104. What part of the GI tract absorbs dietary vitamins?
    S. intestine (limited in l. intestine)
  105. These vitamins dissolve in dietary fats and move across the villus epithelium by passive diffusion.
    Fat-soluble vitamins (A, D, E, K)
  106. This vitamin binds to specific mucosal receptor sites in the terminal ileum. Is taken up by endocytosis.
    Vitamin B12 - intrinsic factor complex
  107. What type of vitamins are absorbed easily by diffusion or via active or passive transport?
    Water-soluble vitamins (B vitamins, C)
  108. The absorption of iron and calcium is largely limited to what part of the s. intestine?
  109. In what part of the digestive system does absorption of electrolytes occur?
    S. intestine
  110. These electrolytes are absorbed in the s. intestine.
    • Iron in duodenum
    • Calcium in duodenum
    • Sodium
    • Potassium
  111. How do potassium ions move across the intestinal mucosa?
    Passively - facilitated diffusion
  112. Calcium absorption is closely related to what 2 factors?
    • Blood levels of ionic calcium
    • Vitamin D in the s. intestine
  113. How many L of water enter the s. intestine daily?
    9 L
  114. How is 95% of the water in chyme absorbed?
    Osmosis in the s. intestine
  115. What is the normal rate of water absorption?
    300 to 400 ml per hour
  116. The absorption of these ions occurs in the small intestine and is coupled to active absorption of glucose and amino acids.