AP2- test 5

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AP2- test 5
2011-12-19 13:52:59

Test 5
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  1. What are the two main groups of the Digestion system?
    • Alimentary Canal
    • Accessory Digestive organs
  2. What is the function of the alimentary canal?
    • Digest- Break down food to smaller fragments
    • Absorb fragmented food into the blood
  3. What organs are included in the alimentary canal?
    Mouth, pharynx, esophagus, stomach, sm intestines, lg intestines, anus
  4. What is the function of the accessory digestive organs?
    Aid in digestion
  5. What are the accessory digestive organs?
    teth, tongue, gall bladder, salivary glands, pancreas
  6. What are the 5 Digestive processes?
    • Ingestion
    • Propulsion
    • Mechanical Digestion
    • Chemical Digestion
    • Absorption
    • Defecation
  7. What is Ingestion?
    taking food into the digestive tract, via mouth
  8. What is propulsion
    • moving food through the alimentary canal
    • Swallowing- Voluntary
    • Peristalsis- IV, contracts and relaxe muscles in the walls to push food through the canal
  9. What is Mechanical digestion?
    • prepares food for chemical digestion
    • Chewing, mixing fodo with saliva, churning food in stomach, segmentation
  10. What is Segmentation?
    Mixes food with digestive juices, increases rate of absoprtion
  11. What is Chemical digestion?
    a series of processes that break down foods by enzymes secrete in the alimentary canals
  12. What is absoprtion?
    Absoption of vitamins, minerals, and water from the alimentary canal to blood, mainly in the sm. intestine
  13. What is defecation?
    elimination of indeigestible substances from the body
  14. What is included in Splancnic Circulation?
    • The Celiac Trunk
    • Mesenteric Vessels
  15. What is the Splancnic Circuit?
    arteries that branch off of the celiac trunk to serve digestive organs and the hepatic portal circulation
  16. What is Hepatic Portal Circulation?
    collects nutrient rich venous blood from digesive organs and brings it to the liver which collects and stores nutrients
  17. What are the 4 tunics of the alimentary canal?
    • Mucosa
    • Submucosa
    • Muscularis Externa
    • Serosa (adventitia)
  18. What is the function of the mucosa layer?
    • Secrete mucus, digestive enzymes and hormons
    • Absorb nutrients into blood
    • Protect agains infection
    • Made of Simple Columnar Epithelium
  19. What makes up the submucosa
    Areolar CT, containg capillaries, lyphatic vessels, lymphatic follicles and nerve fibers
  20. What is the Muscularis Externa responsible for?
    segmentation, peristalsis and forms sphincters
  21. What is the Serosa?
    Visceral peritoneum
  22. What is the Parasympathetics affect on Gi activity? Parasympathetic?
    • Increases
    • Decreases
  23. What is the function of the mouth?
    Food ingestion
  24. What is the function of the teeth?
  25. What is the function of the tongue?
    Create Bolus, compacted food
  26. What doe the intrinsic and extrinsic muscles of the tongue do?
    • Intrinsic- change shape of tongue
    • Extrinsic- move tongue forward, side to side
  27. What are the 3 salivary glands?
    Parotid, submandibular, sublingual
  28. Which Salivary glands are intrinsic?
    Submandibular, sublingual
  29. What is the extrinsic salivary gland?
    parotid gland
  30. What is the compostion of saliva/
    97-99.5% water
  31. What defenses does the saliva contain?
    • Ig A
    • Lysozyme-antibacterial enzyme
    • cyanid compound
    • defensins
    • Amylase- breaks down startch
  32. What is the purpose of the pharynx
    Food passes through the oropharynx and laryngopharynx
  33. What is the purpose of the esophagus?
    Pierces the diaphragm at the esophageal hiatus to join the stomach at the cardiac orific which is surrounded by the gastroesophageal sphincter
  34. What are the two phases of Deglutiiton (Swallowing)?
    • Buccal Phase- voluntary, bolus is pushed into pharynx
    • Pharyngeal Esophageal phase- Pharynx and esophagus, food is moved by peristalsis
  35. Where is the swallowing center located?
    Pans/Medulla Oblongata
  36. What is Barett's esophagus?
    when stomach juices reach the esophagus causes a change in the epithelium
  37. What is the function of the stomach?
    initiates Chemical breakdown of Protein
  38. What is the mucosa of the stomach made of?
    • Simple columnar epithelium with goblet cells
    • Gastric pits > Gastric Glands
  39. What movement occurs in the stomach?
  40. What do Gastric pits contain?
    Gastric Glands which secret gastric juices
  41. What are the cells of the gastric glands?
    • Mucous neck Cells
    • Parietal (Oxyntic) cells
    • Chief (zymogenic) cells
    • Enteroendocrine cells
  42. What do Mucous neck cells produce?
    Avidic mucous
  43. What do Parietal (Oxyntic) cells produce?
    • HCl and intrinsic factor
    • HCl causes stomach's acidity
    • Intrinsic factor- glycoprotein needed to absorb B-12
  44. What do Chief Cells produce?
    • Pepsinogen (inactive pepsin), which is activated by HCl
    • Pepsin is a protein digesting enzyme
  45. What do Enteroendocrine Cells produce?
    • Histamine and Serotonin- act locally as paracrines
    • Somatostatin- influences other digestive organs
    • Gastrin- Stimulates HCl release
  46. What are the 3 phases of regulation of gastric secretion?
    • Cephalic
    • Gastric
    • Intestinal
  47. What occurs during Cephalic phase?
    • Occurs before food enters the stomach
    • Activated by sight/smell/thought of food
    • Stimulates the stomach to start secretions
  48. What occurs during the gastric phase?
    • As food enters stomach, stretch receptors are stiulated, causes stomach glands to secrete
    • Stimuli are Distension, peptides, low acidity
  49. What is the chemical stimulai for the Gastric Phase?
    • Provided by caffeine, rising pH, partially digested proteins.
    • Causes rise in pH > gastrin release > stimulate HCl > provides acidic condition
  50. What is HCl production stimulated by?
    • Ach
    • Gastrin
    • Histamine
  51. What is the alkaline tide?
    Blood leaving the stomach is more alkaline due to the stomach taking most of the HCl from the blood
  52. What are the two componenets of the Intestinal phase?
    Excitatory and Inhibitory
  53. What occurs during the excitatory phase of the Intestinal phase?
    • It's brief
    • As partially digested food fills the Duodenum, Enteric gastrin is secreted to push food into the duodenum from the stomach
  54. What occurs during the inhibitory phases of the Intestinal phase?
    • aka, enterogastric reflex
    • When duodenum is filled with chyme, enterogastrones are released and they decrease gastric secretions and motility
  55. What are enterogastrones?
    • Secretin
    • CCK
    • VIP
    • GIP
  56. What are the pacemakers of gastric motility?
    Set the rhythm for the stomachs movements. Called cells of Cajal, AP is sent out 3x per minute
  57. How long does it take for the stomach is empty?
    3-4 hours
  58. What are the plicae circularis?
    folds of the mucosa and submucosa, causing food to spiral, dealrying transit time and mixing fodo with digestive enzymes
  59. What are villi?
    • Finger- like rojections that absob fatty acids and monoglycerides.
    • They contain Cripts of Lieberkuhn, which secrete intestinal juice
  60. What are microvillia
    • projections that line the villia
    • Contain Brush Border Enzymes, They absorb disaccharides, carbs, paptidases and protein
  61. What is the submucosa of the small intestine
    • Ileum: Peyer's patches- prevent bacteria from entering the blood stream
    • Duodenum: Brunner's Glands- secrete HCO3- mucus to neutralize acidic chyme from stomach
  62. What is the liver's digestive function?
    To produce Bile
  63. What doe the bile salts travel in?
    Enterohepatic Circulation, they are not eliminated, but recycled
  64. What do bile salts do?
    • Emulsify fats
    • facilitate fate and cholesterol absorption
    • solubize cholesteral contained in bile
  65. What are Bile pigments?
    Bilirubin converts to urobilinogen and sterocobilinogen
  66. What is the anatomy of a liver lobule?
    • It is hexagonal
    • Plates of hepatocytes
    • Sinusoids
    • Kupffer cells
    • Triad
  67. What are hepatocytes?
    liver plates, they make lines on the inside of the liver lobule
  68. What is located in the center of the liver lobule?
    A Central Vein
  69. What is located on each corner of a liver lobule?
    • A portal Triad:
    • hepatic artery- supplies O2
    • Hepatic Portal Vein- Venous blood with nutrients
    • Bile Duct
  70. What is a liver sinusoid on a hepatocyte?
    bring blood from the triad to the central vein
  71. What is the function of Kupffer cells?
    remove Debris from the blood
  72. What is the function of the Gall Bladder?
    Stores and concentrates bile
  73. What stimulates contraction of the gall bladder?
    • Parasympathetic
    • CCK: released by intestines when food enters duodenum, stimulates pancrease and relaxes sphincter of oddi
  74. What is the anatomy of the pancreas?
    • Head, body, tail
    • Hepatopancreatic duct
  75. What is the pH of pancreatic juice and why?
    8.0, to neutralize the acidic chyme in the duodenum
  76. Describe pancreatic enzymes
    They are inactive in the pancreas and are activated by duodenal enterokinases in the duodenum
  77. What regulates pancreatic secretions?
    • Parasympathetic
    • CCK- Stimulates pancreatic secretions
    • Secretin- stimulated in response to HCl in intestines, targest cells to secrete HCO3-
  78. What is the acidic tide?
    When the alkaline tide of the stomach becomes neutralized near the pancrease
  79. What is the movment of the Sm. Intestine?
  80. What is the gastroileal reflex?
    Enhances segmentation of the ileum so food reaches the ileocecal valve
  81. How does Gastrin affect the ileocecal valve?
    secreted by the stomach it increases the ileum's motility and relaxes the sphincter
  82. What is the function of the Lg Intestine
    Absorb water from indigestible foods and then to eliminate them
  83. What is the function of bacterial flora?
    • Ferment indigestible Carbs, which creates gas
    • Synthesize B and K vitamins
  84. What is the movemtn of the Large intestine?
    • Slow, short lived peristatlic contractions
    • Haustral contractions
    • mass movments
  85. Describe Haustral Contractions
    slow segmenting movements that occur every 30 minutes
  86. Describe Mass movements
    • long, slow powerful contractions that push feces into the rectum, occurs 3-4x per day right after a meal
    • aka gastrocolic reflex
  87. Describe the defecation reflex
    distension of the rectum sends an impulse to the CNS, which contracts the rectal walls, and relaxes the internal rectal sphincter