Digestive System

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Digestive System
2011-12-11 19:51:02
Digestive System

A & P II
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  1. List the functions of the Digestive System
    • Ingestion
    • Mechechincal Digestion
    • Chemimal Diegestion Secretion
    • Secretion
    • Absorbtion
    • Excretion
  2. What are the 4 layers of the digestive track?
    • Serosa
    • Muscularis Externa
    • Submucosa
    • Mucosa
    • muscularis mucosa, lamina propria, epithelium linning
  3. Describe the Serosa:
    Outer tough connective tissue membrane for PROTECTION
  4. Describe the Muscularis Externa:
    Longitutdal & Circular muscle layers for CONTRACTION
  5. Describe the Submuscosa:
    Loose connective tissue = blood vessels & glands for SECRECTION
  6. Describe the Mucosa:
    • Made of three layers=
    • Muscularis Mucosa (or Interna)
    • Lamina Propria (connective tissue)
    • Epithelium Linning (inner most)
  7. What does ENS stand for ?
    Enteric Nervous System
  8. Describe the ENS / what special characteristic does it have ?
    The G.I. Tract LITTLE BRAIN that functions independantly
  9. What are the functions of the Enteric Nervous System ?
    • Sensory Neurons = montior GI tension, chemical & hormone levels.
    • Monitor Interneuronal Circuts = controls GI muscles motility, blood flow & secretions
  10. What does the Enteric Nervous System consist of :
    • Myenteric Plexus
    • Submucosa Plexus
    • Parasympathetic
    • Symphathetic
  11. Describe the Myenteric Plexus of the ENS:
    Linear chains of neorons located BETWEEN the Longitudal & Circular muscle layers

    Control GI Muscels tone, contraction intensity, frequency & velocity
  12. Describe the Submucosal Plexus of the ENT:
    nonlinear neurons SCATTERED in the submucosa

    Controls intertinal secretions, digestion, and absorption
  13. What does the parasympethetic nervous system do to the ENS?
    Activates ENS
  14. What does the sympethetic nervous system do to the ENS?
    Inhibits the ENS
  15. ________ are protien catalystis that speed up the digestion chemical reactions.
    Protien Catalyistis
  16. Protien Catalyists speed up digestion @ _______ temperature.
    Body temperature.

    They are not altered during the reaction, but are SENSITIVE to changes in Temperature & pH
  17. Protien catalyists are _________ enzymes that use water to split food molecules.
  18. Mastication happens where? explain it.
    • Mouth, is mechanical
    • breaks down & lubicrates food for easy swallowing.
    • increases surface area for enzyme action
  19. What chemical digestion happens in the mout?
    Salivary Amylase tuens starch into Disaccharides
  20. Name the 3 types of salivary glands :
    • Parotid
    • Sublingual
    • Submandibular
  21. Where are the Parotid Glands & what do they do?
    • inferior to the zygomatic arch
    • Serous Secretion + Amylase
  22. Where are the Sublingual Glands & what do they do?
    • under the base of the tongue
    • Mucous secretion only (mucins)
  23. Where are the Submandibular Glands & what do they do?
    • on inner surface of the mandible
    • Serous + Mucous + Amylase
  24. What are the phases of swallowing?
    • 1. Buccal
    • 2. Pharyngeal
    • 3. Esophageal
  25. Describe the Buccal Phase of swallowing:
    the tongue pushes the BOLUS of food from ORAL Cavity into the OROPHARYNX
  26. What is the only phase of swalling you conciouslucontrol?
    Buccal phase
  27. Describe the Pharayngeal Phase of swallowing:
    Soft Palate closes Nasopharynx & Epiglottis closes the Laryngopharynx
  28. Choking is most likly to occure during what phase?
    • Pharayngeal phase
    • getting stuck in the laryngopharynx
  29. Describe the Esophageal Phase of swallowing:
    • A. Upper Esophageal spincter opens
    • Peristalis propels bolus down esophagus
    • B. Cardiac spincter opens & bolus enters stomach
  30. What layer does the Esophaghagus have instead of the sercosa?
  31. What do the rugae do in the stomach?
    allow it to contract when empty & expand when full
  32. Name the muscle layers of the stomach:
    • Rugae
    • Oblique (over mucosa)
    • Circular
    • Longitudal
  33. What are the 4 functions of the stomach?
    • Storage
    • Mechanical digestion
    • Chemical digestion
    • Absorbtion (of liquids &drugs)
  34. The ________ holds food during feeding.
  35. _________ Digestion in the stomach makes liquid ______ and pushes it into the small intestine.
    Mechanical digestion, grinding waves of the 3 muscle layers, make Chyme
  36. In chemicl digestion of the stomach, _____________ is protiens begin digestion.
    Pepsin Protiens
  37. Absorbtion in the stomach is limited to what?
    Water, Alcohol, & Drugs
  38. What are the 4 parts of the gastric gland?
    • Mucous neck cells
    • Parietal cells
    • Chief cells
    • G cells
  39. What do the mucous neck cells of the Gastric Gland do?
    secrete protective mucous (mucins)
  40. What do Parietal Cells of the Gastric Gland do?
    secrete Hydrochloric Acid & Intrinsic Factor
  41. What do the cheif cells of the gastric gland do?
    secrete Pepsinogen & Gastric Lipase
  42. What do G-cells of the Gastric gland do?
    secrete the hormone Gastrin which stimulates gastric secretion
  43. Pepsinogen is converted to the ative enzyme Pepsin in the stomach lumen by ________ ______ .
    HCL = Hydrocloric Acid
  44. _______ digests protiens to small __________.
    Pepsin digests PROTIENS into POLYPEPTIDES
  45. Gastric Lypase starts _________ digestion.
  46. What are the layers of the Small Intestine?
    • Serosa (bottom)
    • Muscularis Externa
    • Submucosa
    • Mucosa
  47. What is the "modification" of the small intestine?
    the mucosa layer has 4-5 million villi
  48. What are the villus of the small intestine covered with?
    Columnar Epithelium & Goblet Cells
  49. What do the capillaries inside the villus do?
    Absorbtion of Nutients
  50. Lymphadic Capillaries are also known as =
    • Lacteal
    • found in small intestine, inside the villi
    • aide in lipid digestion product absorbtion
  51. What does an Absorptive cell do and where is it found?
    epithelium cell of the villi = digestion & absorbtion
  52. What does a Goblet cell do and where is it found?
    secrete mucous on villi
  53. What does an Endocrine cell do and where is it found?
    Intestinal Hormones created locally on villi
  54. What does a Paneth cell do and where is it found?
    Macrophage found in villi
  55. _______ propel chyme along the intestine.
  56. ________ moves chyme back and forth to it thoroughly with digestive enzymes.
  57. Enzymes from the ______ & ______ complete digestion of protien, starch, disaccharide sugars and fat.
    Pancreas & Small Intestine
  58. Segmentation & Peristalsis are part of _______ digestion in the small intestine.
  59. Enzymes & Bile are part of _____ digestion in the small intestine.
  60. The Gallbladder empties ______ into the small intestine to aide in fat digestion.
  61. Describe the Pancreas:
    • 5 inch long extension from the Duodenum to the Spleen
    • Consists of 4 parts (head, neck , bady, & tail)Describe the Pancreas:
  62. What cells are found in the Pancreas?
    95-98% are EXocrine producing digestive enzymes

    Some are ENDOcrine cells in pancreatic islets which produce hormones
  63. What are Acinar cells & where they found?
    EXocrine cells that secrete digestive enzymes into the ducts of the Pancreas
  64. What are Ductal cells & where they found?
    secrete a BICARBONATE Solution that neutralizes the acidic Chyme from the stomach and PROTECTS the mucosa of the Duodenum as the food moves from the stomach into the duodenum
  65. Protiens can only be absorbed as a _______ amino acid.
  66. Pancreatic Juice is made of what?
    Bicarbonate Solution & Digestive Enzymes
  67. Protiens are digested by what Pancreatic Enzyme & Where are they activated?
    Proteolyic Enzymes = activated in the Duodenum
  68. The Proteytic Enzymes digest protiens & polypeptides into what?
    • Tripeptides
    • Dipeptides
    • Single Amino Acids
  69. Starch is digested by what Panreactic Enzyme?
    • Pancreatic Amylase
    • it digested starch into disaccharides
    • ** this is the sams as in the mouth **
  70. Fats are made of what?
  71. What pancreatic enzyme digests fats?
    Paancreatic Lipase Enzyme
  72. Digestion of each triglyceride yields what?
    One Monoglyceride molecule & Two fatty acid molecules
  73. Bile from the _______ is required so that pancreatic lipase can digest ______ more effeciently.
    • Liver
    • to digest Fats
  74. Bile flows from ______ to _____ to mix with & emulsify fats.
    from the Gallblader, down the bile duct and into the Duodenum
  75. _________ is breaking fat drops into very small droplets for effecient enzyme action.
  76. Bile aides in the ______________ of fats.
    Absorbtion of digested fats
  77. Bile is a medium for _____ & ______ excretion by the liver.
    Bilirubin & Cholesterol
  78. Name the 4 lobes of the Liver:
    • Left
    • Right
    • Caudate
    • Quadrate
  79. The liver lobes contain microscopic liver _______.
  80. Liver Lobules consist of rows of liver ______ and rich blood supply.
  81. Blood is supplied to the liver by branches of the _________ & _________ at the six corners of each lobule.
    Hepatic Artery & Portal Vein
  82. Blood flows toward the central vien of each liver lobule through the _________, which is surrounded by hepatocutes.
  83. Liver macrophages are called ___________.
    Kupffer Cells
  84. Kupffer cells take over ___________ in the liver, cleaning the blood.
  85. Bile Canaliculi are what?
    bile ducts that collect bile from each hepatocyte and delivers it into the Billary system
  86. Bile flows from the liver through _______ ducts into the _________.
    Hepatic ducts into the Gallbladder
  87. The common hepatic duct & the cystic duct from the gallbladder untie to form what?
    The Common Bile Duct
  88. Common Bile duct unites with the _____ duct.
  89. Bile & Pancreatic juices enter the _______ via the common bile duct.
  90. Functions of the Liver:
    • Carbohydrate, Lipid, & Protein metabolism
    • Storage of glycogen
    • Removal of hormones, antibodies, & metabolic waste products
    • Detoxification of drugs & toxins
    • Phagocytosis by Kuffer Cells
    • Plasma Protien Synthesis
    • Bile synthesis & secretion
  91. ______ are located on the microvillei of instestinal cells.
    Brush-Border enzymes
  92. ________ digests tri & depeptides into single amino acids.
  93. ______ digests fats into glycerol and free fatty acids.
    Intestinal Lipase
  94. Disaccharides digest disaccarides into individual _______.
  95. _____ digests Sucrose into Glucose & _______.
    • Sucrase
    • Fructose
  96. _____ digests Maltose into Glucose & ________.
    • Maltase
    • Glucose
  97. _____ digests Lactose into Glucose & _______.
    • Lactse
    • Galactose
  98. Absorption is the transfer of substances into _______ and then into ________.
    Absorptive cells then into Blood or Lymph capillaries
  99. Villi & Microvilli provide what of absorptive cells?
    very large surface area for absorption
  100. Where are most foods, water, electrolytes and vitamins absorbed?
    Small Intestine
  101. In Lacteal : fats & fat soluble vitamins in ______.
  102. Mucosa have no villi and are covered in what type of epithelium?
    Simple Columnar epithelium
  103. Submucosa has deep _____ with intestinal glands that secrete _________.
    • Crypts
    • Mucus
  104. What are the layers of the Large Intestine?
    • Serosa
    • Muscularis Externa
    • Submucosa
    • Mucosa
  105. In the large instine, what happens to undigested food?
    it is digested by bacteria
  106. What vitamins are formed in the large intestine? and by what?
    • B & K
    • By Bacteria
  107. What is absorbed in the Large Intestine?
    • Water
    • Electrolytes
    • Vitamins
    • Bile Salts
  108. Feces is formed by what?
    Bacterial Action
  109. What is Mass Movement?
    Propelling of feces in the large intestine by contractions
  110. The Desire for defecation is initiated when?
    When mass movement contractions in the colon push feces into the Rectum
  111. Tonic contractions of the _______ & ______ prevent actual defecation execept in ____.
    • Internal & External Sphincters
    • except in Babies
  112. The internal anal sphincter is made of what type of muscle?
    Smooth = this makes it involuntary
  113. The internal anal spincter relexes by the parasympathetic ______ nerve stimulation.
  114. The internal spihncter tightens or constricts via stimulation from what nerve?
    Hypogastric Nerve
  115. The external anal sphincter is made of what muscle type?
    Skelatal, making it voluntary
  116. The external anal spincter is innervated by the ________ nerve and is under ________ control.
    • Pudendal nerve
    • Voluntary conscious control
  117. What are the 3 reflexes of Defecation?
    • Intrinsic Reflex
    • Parasympathetic Reflex
    • Conscious Control
  118. The Intrisic Reflex includes what?
    • Myenteric Plexus Reflex which triggers Peristalsis in the colon & Rectum
    • Too weak to cause defication
  119. The parasympatheic reflex involves what?
    transmission of signal to the spinal cord via the PELVIC Nerve & intesified Peristalsis
  120. Concous control includes what?
    • relaxation of the external spincter
    • contraction of abdominal muscles
    • emptying of the deciending & sigmoid colon and rectum