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2014-07-24 13:41:54

Biochem Exam 1
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  1. Stomach cells that secrete mucus and bicarbonate
    neck cells
  2. Stomach cells that secrete HCl and intrinsic factor
    Parietal cells
  3. Stomach cells that secrete enzymes (pepsinogen and gastric lipase)
    Chief cells
  4. Stomach cells that secret hormones
    Enteroendocrine cells ("G Cells")
  5. Gastric juice contains:
    • Water
    • Electrolytes
    • Intrinsic factor
    • Hydrochloric acid
    • Enzymes
    • Mucus
  6. Not enough intrinsic factor causes
    Malabsorbtion of Vitamin B12
  7. Denatures proteins, converts pepsinogen to pepsin, releases nutrients rom organic complexes
    Hydrochloric acid
  8. pH of gastric juice
  9. What don't we digest in the stomach?
  10. What don't we start to digest in the mouth?
  11. Stomach hormone that opposes gastrin action
  12. Effect of gastrin on the stomach
    Stimulates HCl secretion and mucosal growth
  13. Stimulants for release of gastrin
    Antrum distention; vagus nerve impulses triggered by site/smell of food; proteins
  14. Stimulants for release of secretin
    Acidic chyme in duodenum
  15. Effect of secretin on the stomach
    Stimulates pesinogen secretion; decreases gastric motility
  16. Stomach hormone that decreases gasric emptying
    Cholecystokinin (CCK), Gastric inhibitory peptide (GIP)
  17. Stimulants for release of CCK
    Fat or protein-rich chyme in duodenum
  18. Stimlants for GIP
    Fatty acids, amino acids and some carbs
  19. Stimulant for release of motilin
    Fasted state
  20. Motilin effect on stomach
    Increases motility
  21. Chyme is released to small intestine through pyloric sphincter at a rate of
    About 2 teaspoons a minute
  22. Gastric emptying takes how long following a meal?
    1-6 hours (1-2 hours for liquid meal, 2-6 hours for solid meal)
  23. Feeling of fullness
  24. Hunger
    Physiological need to eat
  25. Appetite
    Psychological want to eat
  26. Controlled by the hypothalamus
    Satiety, hunger, appetite
  27. Hypothalamus works by
    Integration of peptide hormones (ghrelin, CCK, insulin), macronutrients (carbs, lipids, proteins), and adipokines (leptin, adiponectin)
  28. Least full to most full
    • Fat
    • Carbohydrates
    • Fiber
    • Protein
  29. Fastest to slowest gastric emptying
    • Fat
    • Starchy/processed carbohydrates
    • Fiber
    • Protein
  30. Large meals (increase in stomach distention) are emptied faster or slower than smaller meals?
    Faster - Distention causes gastrin secretion, increases motility in the stomach (HCl)
  31. Three portions ofhte small intestine
    • Duodenum
    • Jejunum
    • Ileum
  32. Primary site for digestion in small intestine
  33. Primary site for absorption of the small intestine
  34. Ileum connects to large intestine through
    Ileocecal sphincter
  35. Chyme first enters small intestine through
    Pyloric sphincter (duodenum)
  36. Four layers of the SI
    • Mucosa
    • Submucosa
    • Muscularis externa
    • Serosa
  37. Layer of SI that produces and releases enzymes, hormones, and digestive juices
  38. Connective tissue thath regulates secretions from mucosal glands, mucosal movements and blood flow
    Submucosa (submucosal plexus)
  39. Villi is made up of
    Mucosa, submucosa
  40. Intestinal contents move through the SI at a rate of
    1-2 cm per minute
  41. Chyme is in SI for how long
    3-8 hours
  42. Inactive microvilli (immature) are found
    in the crypts of lieberkuhn
  43. Mature microvilli are replaced
    Every few days
  44. What do you usually make in the Smooth ER?
    Lipids, some enzymes
  45. Enterocytes have a life span of
    3-5 days
  46. Inactive enterocytes migrate from crypts of lieberkuhn to
  47. Enterocytes are functional on villi tips for
    2-3 days
  48. After 2-3 days ofb eing a functional villi, enterocytes are
    Sloughed off into the lumen, recycled
  49. 45% of energy necessary for enterocytes to function are supplied by
    Nutrients passing through (diet)
  50. After a few days of starvation, the GI tract
  51. Optimal GI function requires constant supply or fasts and binging?
    Constant supply, otherwise enterocytes die off, no absorption (malnutrition)
  52. Intestinal permeability (leaky gut) is regulated by
    Proteins as part of tight junctions, adherens junctions and desmosomes
  53. What will increase intestinal permeability (leaky gut)?
    • Inflammatory compounds
    • Psychological stress
    • High fat diet/bile
  54. Intestinal permeability foundin patients with
    Food allergies, celiacs, irritable bowl, crohns
  55. Digestion in the SI by Brush Border enzymes (secreted by submucosal plexus in enterocytes)
    Proteins and carbs
  56. Low blood sugar causes secretion of
  57. Actual production of brushborder enzymes occurs in the
    Mucosa layer
  58. Accessory organs
    • Liver
    • Pancreas
    • Galbladder
  59. Bile is made in the
    Liver, stored in the gallbladder
  60. Removal of gallbladder leads to what of the bile?
    Less concentration
  61. Endocrine cells secreted in teh pancreas
    • Insulin
    • Glucagon
  62. Exocrine cells of the pancreas secrete
    Pancreatic juice
  63. Pancreatic juice composition
    • Bicarbonate - neutralizes acidic chyme
    • Electrolytes
    • Digestive enzymes
  64. Secretion of bicarbonate takes the pH of chyme from
  65. Improper pancreatic function leads to
    Malabsorbtion (fatty stools)
  66. Digestion in the SI by pancreatic enzymes
    Carbs (50%), lipids(80-90%), proteins(50%)
  67. Lipids are digested in the
    Mouth, stomach, small intestine (by pancreatic enzymes)
  68. Secretin stimulates
    Bicarbonate secretion from pancreas
  69. Secretin release is stimulated by
    Acidic chyme in duodenum
  70. Cck stimulates secretion of
    Enzymes and biccarbonate
  71. CCK - stimulant for release (pancreas)
    Fat or protein-rich chyme in duodenum
  72. Gastric inhibitory peptide effect on pancreas
    Stimulates insulin synthesis and secretion
  73. Most digesion occurs where, due to what?
    Small intestine, due to pancreatic enzymes
  74. largest organ in the body
  75. Cells of the liver are called
  76. Liver receives blood directly from the
    Small intestine through portal vein
  77. Liver filters
    At a high rate
  78. Liver contains pores large enough for
    Proteins to enter
  79. Macrophage-containing cells in the liver
    Kupffer  cells
  80. Liver functions in metabolism (carbs)
    • Glycogen storage
    • Conversion of sugars to glucose
    • Gluconeogenesis
  81. Liver function in metabolism (proteins)
    • Formation of plasma proteins
    • Interconversion of amino acids
    • Urea formation
  82. Liver functions in metabolism (lipids)
    • Synthesis of choleterol, phosphlipids, lipoproteins
    • Oxidation of fatty acids for energy use in other tissues
    • Synthesis of fat from carbs and proteins
  83. Other live functions
    • Vitamin storage
    • Iron storage
    • Synthesis of clotting factors (using vitamin K)
    • Detoxification of drugs, hormones, etc. (Contains Phase 1 and Phase II detox enzymes)
  84. Where is bile produced?
  85. Bile is
    Synthesized in the liver (from cholesterol), stored in the gallbladder, introduced to the duodenum to help break down lipids
  86. Composition of bile
    • Cholesterol
    • Phospholipids
    • Bile pigments (bilirubin and biliverdin)
    • Water
    • Electrolytes
    • Bicarbonate
  87. If bile is too concentrated in the gallstones, what happens?
    Cholesterol will precipitate out, causing gallstones
  88. Effect of CCK on the gallbladder
    Contracts gallbladder releasing content
  89. What happens to bile salts in gallbladder?
    Increase (more concentrated)
  90. Chol-something=
    • Bile something (acid or salt)
    • Cholate or cholic acid (unconjugated acid) 
    • Glycocholate (acid or salt conjugated) 
    • Taurocholate (acid or salt, conjugated)
  91. How much secreted bile acids and bile salts are reabsorbed in SI?
  92. What happens to the 5% of bile that isn't reabsorbed?
    Excreted infeces
  93. Reabsorbtion of bile happens in the
  94. Reabsorbed bile acids are transported via the
    Portal vein to the liver for reconjugation
  95. Old bile and new bile is transported to the
    Gallbladder for storage and concentration
  96. Enterohepatic circulation
    Movement of bile from liver to gallbladder, to small intestine, and then reabsorbtion from ileum through hepatic vein back into the liver
  97. Large intestine is also known as the
  98. Unabsorbed material from SI enters LI through
    Iliocecal valve
  99. Sections of LI
    • Cecum
    • Ascendign
    • Transverse
    • Descending
    • Sigmoid
  100. What happens in the LI?
    No digestion, only fermentation and some absorbtion
  101. How long it takes material to get through LI
    12-70 hours
  102. Most water absorbtion happens in the
  103. 1L of chyme is reduced to
    About 200 g of feces after 12-70 hours
  104. Material in rectum signals what
    Defecation reflexes by distentioni signaling myenteric plexus to start peristalsis
  105. Feces exit via
    Anal canal
  106. Motilin effect on LI
    Increase motility, stimulated by fasting state
  107. Most bacteria in the LI is
  108. Colonic salvage
    Whats left after fermentation of unabsorbed cabohydrates and proteins into short chain fatty acids and gas
  109. Good bacteria are called
  110. Food for good bacteria (fermentable fiber)
  111. Food that contains pre- and probiotics
  112. Products of fermentation
    Short chain fatty acids
  113. What can be fermented?
    Proteins and carbohydrates. Lipids can't be fermented