Digestive system

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Digestive system
2013-04-29 14:36:38

lab quiz 1
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  1. how does digestion contribute to homeostasis?
    • 1-break down food 
    • 2-absorbs vitamins, water,minerals fuel needed for the body
    • 3-eliminates wastes
  2. Define digestion
    the process of breaking down large food molecules into smaller molecules that can be absorbed by the body
  3. what are the four tunics of the GI tract
    • 1-mucosa
    • 2-sumucosa
    • 3-muscularis
    • 4-serosa
  4. describe the mucosa layer
    mucous membrane, surrounded by lumen in the contact with food.
  5. how many layers does mucosa tunic have
    three layers
  6. what are is the name of the 3 mucosa layers
    • 1-epithelium
    • 2-lamina propria
    • 3-muscularis mucosae
  7. what type of cells does the epithelium consist of in the mucosa tunic
    simple columnar epithelium
  8. what is the function of the epithelium in the GI tract
    secretion and absorption
  9. what is the function of the lamina propria?
    to support the epithelium and bind it to the muscularis mucosae
  10. What type of tissue makes up lamina propria
    areolar connective tissue
  11. what can you expect to find in the lamina propria
    1-blood and lymphatic vessels-routes by which nutrients absorbed by the GI tract reaches other tissues

    2-MALT-mucosa associated lymphatic tissue

  12. what type of cells creates muscularis mucosae?
    smooth muscles
  13. what is the function of muscularis mucosae?
    it creates folds which increase the surface are for digestion and absorption. The movement of the muscularis mucosae ensures all absorptive cells have contact with intestinal content
  14. what type of tissue makes up submucosa?
    areolar connective tissue, covered by epithelium
  15. what kind of vessels can you find in the submucosa?
    1-blood and lymphatic vessels that receive absorbed food molecules

    2-an extensive network of neurons known as submucosal plexus
  16. what is the function of the submucosal plexus?
    regulate the secretion and activity of the GI Track
  17. What is the function of the submucosa?
    binds mucosa to muscularis and supports the mucosa
  18. what type of tissue makes up the muscularis tunic of the GI tract?
    • -two layers of smooth muscle
    •         1-circulatory muscles
    •         2-longitudinal muscles
  19. what is the function of muscularis tunic of the GI tract?
    to help break down food, mix it with digestive secretions and propel food along the tract by creating involuntary contraction
  20. what is the name of the  neuron network found in muscularis?
    myenteric plexus
  21. what is the function of the myenteric plexus?
    control motility (movement) in strength and frequency of the muscularis
  22. is the serosa considered to be serous membrane?
    yes, the serosa is considered to be serous membrane
  23. what is serosa composed of?
    areolar connective tissue line with a layer of simple squamous epithelium plus fibrous connective tissue
  24. what is the function of the serosa?
    creates lubrication fluid for the organs to glide. its used as a hanger for the digestive system
  25. Describe the general anatomy of the digestive system
    mouth, pharynx, esophagus, stomach, small intestine and large intestine
  26. what are the two main group of organs or regions with the digestive system?
    GI Tract and accessory organs
  27. name the two organs that make up the alimentary canal or GI tract
    GI track and accessory organs
  28. name the accessory organs
    teeth, tongue, salivary glands, liver pancreas and gullbladder
  29. which areas of the digestive system uses stratified squamous epithelium?
    the esophagus and the rectum
  30. what is peritoneum?
    its serous membrane
  31. what is the function of the peritoneum
    to reduce the friction between organs
  32. where does the greater omentum attach to?
    between the stomach and transverse colon
  33. how many layers does the greater omentum have?
    four in total. its composed of a double layer sheet that has two folds
  34. what abundant tissue can you find in the greater omentum?
    adipose tissue
  35. What is the function of the coronary ligament?
    connect the liver to the diaphragm
  36. what is the function of the lesser omentum?
    suspend the stomach and duodenum from the liver
  37. what is the function of the mesentery?
    it bind the jejunum and ileum of the small intestine to the posterior abdominal wall
  38. what is the function of the mesocolon?
    bids the transverse colon and sigmoid colon to the posterior of the abdominal wall
  39. what are the seven function of the digestive system?
    • 1-ingestion
    • 2-secretion
    • 3-mixing and propulsion
    • 4-digestion
    • 5-absorption
    • 6-defecation
    • 7-other
  40. describe ingestion
    taking of food, driving by smell, taste and sight
  41. describe secretion
    production of fluid such as water, acid, buffers, enzymes and waste. about 9 liters a day
  42. describe mixing and propulsion
    propulsion is swallowing and peristalsis(progression of contractions meant to push bolus )
  43. name the two types of digestion
    mechanical and chemical
  44. define chemical digestion
    the breaking of molecular bonds through HYDROLYSIS and ENZYMES
  45. describe absorption stage
    the process which the takes in nutrients, vitamins and other materials the body needs.
  46. name the two types of absorption process
    active and passive
  47. describe the defecation stage of digestion
    the way which the body disposes of waste
  48. describe the "also" stage of digestion
    immune, sensory and water balance
  49. what happens to proteins in chemical digestion?
    proteins become amino acids
  50. what happens to carbs in chemical digestion?
    carbs are converted to simple sugars
  51. what happens to lipid in chemical digestion?
    lipids are converted into fatty acids and glycerol
  52. what happens to nucleic acids in chemical digestion?
    nucleic acids are converted to nucleotides
  53. name the 4 glands found in the mouth?
    • 1-parotid gland
    • 2-sublingual gland
    • 3-submandibular gland
    • 4-buccal gland
  54. what is the function of the 3 glands found in oral cavity?
    to secrete saliva
  55. how much do the salivary gland secrete
    1 to 1.6 liters of saliva a day
  56. what is saliva composed of?
    99.5% water and .05% solutes
  57. what is the function of saliva?
    moisten food, bacteriolysis, begins digestion
  58. what kind of solutes can one expect to find in saliva?
    sodium, potassium, chloride, bicarbonate and phosphate
  59. what kind of enzymes can you find in saliva?
    • 1-salivary amylase
    • 2-lingual lipase
    • 3-immunoglobulin A
    • 4-lysozyme
  60. what is salivary amylase?
    an enzyme that breaks-down starches in the mouth into maltose, maltoriose and alfa-dextrin
  61. what is the function of lingual lipase
    It breaks down dietary triglycerides (fats and oils) into fatty acids and diglycerides. Lingual lipase enzymes becomes activated in the acidic environment of the stomach.
  62. what is the function of Immunoglobulin A?
    to prevent attachment of microbes so they cannot penetrate the epithelium.
  63. what is the function of the enzyme lysozyme?
    kills bacteria
  64. what does the term BOLUS mean?
    lump of food when its reduced to a soft, flexible and easy to swallow.
  65. what is deglutition?
    the process of swallowing
  66. what are the 3 stages of deglutition?
    • 1-voluntary stage-at oral cavity
    • 2-pharyngeal stage-pharynx
    • 3-esophageal stage-esophagus
  67. describe the voluntary stage of deglutition
    bolus moves into the mouth
  68. describe the pharyngeal stage of deglutition
    respiratory passages are closed off. Stimulated receptors send information to deglutition center in the medulla oblongata
  69. describe the esophageal stage of deglutition
    circular and longitudinal muscles contract and bolus moves forward by peristalsis
  70. what are the four layers of the esophagus?
    1-mucosa-non-keratinized stratified squamous epithelium

    2-submucosa-areolar connective tissue

    3-muscularis-contains 1/3 skeletal muscle, 1/3 mix of skeletal and smooth muscle and 1/3 of smooth muscle

    4-adventitia-attached esophagus to surrounding structures
  71. name the two sphincters associated to the esophagus
    1-upper esophageal sphincter-related when larynx is elevated

    2-lower esophageal sphincter-connected at the stomach
  72. what type of cells can you find in the mucosa layer of the stomach?
    • 1-surface mucus cells
    • 2-mucus neck cells
    • 3-parietal cells
    • 4-chief cells
    • 5-G cells
  73. what does surface mucus cells produce?
    secretes mucus at surface of mucosa
  74. what does the mucous neck cell produce?
    secretes mucous in the gastric pit
  75. what is the function of parietal cells?
    secretes hydrochloric acid and intrinsic factors.
  76. what is the function of chief cells?
    secrete pepsinogen and gastric lipase
  77. what is the function of G cells?
    secrete the hormone gastrin
  78. what is the function intrinsic factor in the parietal cell?
    needed for absorption of vitamin B12 for rbc formation
  79. what is the function of HCL in the parietal cell?
    • 1-kill microbes in food
    • 2-denature proteins
    • 3-convert pepsinogen into pepsin
  80. what is the difference between pepsinogen and pepsin?
    pepsinogen is not activated while pepsin is the activated form
  81. what is the function of pepsin?
    break down proteins into peptides
  82. what are peptides?
    two or more amino acids linked together
  83. what is the function of gastric lipase?
    splits triglycerides into fatty acids and monoglycerides
  84. what is the function of gastrin?
    1-stimulate parietal cells to secrete HCL and chief cells to secrete pepsinogen.

    • 2-contracts lower esophageal sphincter
    • 3-relaxes pyloric sphincter
    • 4-increase stomach motility
  85. what is the pancreas composed of?
    small clusters of glandular epithelium cells
  86. what are the cluster of the pancreas composed of?
    1-99% of cluster is composed of Acini

    2-1% of cluster is composed of pancreatic islets
  87. What is pancreatic Acini?
    the exocrine portion of the pancreas that creates pancreatic juice.
  88. what does exocrine mean?
    external secretion
  89. what is the function of pancreatic juice?
    1-buffer acidic gastric juice in chyme

    2-stops the action of pepsin in the stomach

    3-creates proper pH for the action of digestive enzymes in the small intestine
  90. what are pancreatic islets?
    the endocrine portion of the pancreas that secrete glucagon, insulin, somatostatin and pancreatic polypeptide.
  91. what is the function of the exocrine portion of the pancreas?
    to create digestive enzymes
  92. what is the function of the pancreatic islets?
    produce hormones
  93. what type of hormones does the pancreas produce?
    • 1-insulin
    • 2-glucagon
    • 3-pancreatic polypeptide
    • 4-somatostatin
  94. what is the function of insulin?
    control blood sugar levels
  95. what is the function of glucagon?
    deals with low levels of glucose
  96. what is the function of pancreatic polypeptide
    stimulates secretion of ions and water by the intestines and inhibits gastric acid secretion
  97. what is the function of somatostatin?
    inhibits gastrin release
  98. what are the 11 functions of the liver?
    • 1-metabolises carbs, lipids and proteins
    • 2-detoxifies blood
    • 3-removes drugs and hormones
    • 4-synthesis, store and break down glycogen
    • 5-manufactures plasma membrane
    • 6-phagotosis
    • 7-excretion
    • 8-storage of copper, iron and some vits
    • 9-activates vitamin D
    • 10-synthesises bile salt
    • 11-secretion of bile
  99. name the three parts the small intestine is divided into
    • 1-duodenum
    • 2-jejunum
    • 3-ileum
  100. what type of cells can one expect to find in the mucosa layer of small intestine?
    • 1-absorptive cells with microvilli
    • 2-goblet cells
    • 3-enteroendocrine cells
    • 4-paneth cells
  101. what is the function of absorptive cells?
    digestion and absorption
  102. what is the function of goblet cells?
    secrete mucous
  103. what is the function of the paneth cell?
    immunity protection
  104. what are the e hormones enteroendocrine cells produce?
    produce 3 hormones,

    • 1-secretin
    • 2-cholecystokinin(CCK)
    • 3-Glucose-dependent insulinotropic peptide (GIP)
  105. what are the four processes needed to digest food?
    • 1-motility (movement)
    • 2-secretion
    • 3-digestion
    • 4-absorption
  106. what is the daily ingested  or secreted fluid  by the body?
    • 1.0 liter of secreted saliva
    • 2.3 liters of ingested fluid
    • 2.0 liters of gastric juice
    • 1.0 liter of secreted bile
    • 2.0 liters of secreted pancreatic juice
    • 1.0 liter of intestinal juice

    total of 9.3 liters
  107. what is the daily amount of fluid absorbed by the body?
    • 8.3 liters absorbed by the small intestine
    • 0.9 liter absorbed by the large intestine

    total of 9.2 liters
  108. how is the regulation of gastric secretion and motility controlled?
    the nervous system or endocrine system
  109. what are the e phases of digestion?
    • 1-cephalic phase
    • 2-gastric phase
    • 3-intestinal phase
  110. describe the physiology of the cephalic phase of digestion
    sensory inputs sends signals to cerebral cortex and feeding center in the hypothalamus which in  response sends signals to medulla oblongata to parasympathetic preganglionic fibers of the vagus nerve to postganglionic fibers that go the the myenteric and submucosal plexus.
  111. what does the myenteric plexus stimulate?
  112. what does the submucosal plexus stimulate?
    secretion into the stomach
  113. describe the physiology of the gastric phase
    • food reaches stomach, receptors in the stomach will stimulate
    • 1-hormonal reflex
    • 2-neural reflex
  114. what does neural reflex do?
    • 1-motility and secretion
    • 2-increase gastric juices
    • 3-increase contraction of stomach which will force 10-15 ml of food into intestine
  115. what does hormonal reflex do?
    release gastrin
  116. what is the function of gastrin?
    • stimulate
    • 1-gastric glands
    • 2-strengthen contractions
    • 3-tighten lower esophageal sphinceter
    • 4-relax the pyloric sphincter
  117. what releases gastrin?
    • 1-distention of stomach
    • 2-partially digested proteins
    • 3-high pH of chyme
    • 4-caffeine
  118. what is the function of secretin?
    stimulates the flow of pancreatic juice that is rich in bicarbonate ions to buffer the acidic chyme that enters the duodenum
  119. what is the function of Cholecystokinin (CCK)?
    • stimulates secretion of pancreatic
    • juice that is rich in digestive enzymes. It also causes contraction of gallbladder, which squeezes out stored bile
  120. what digestive enzyme substrates (acts on) carbs?
    lingual lipase and pancreatic amylase
  121. what digestive enzyme substrates on protein?
  122. what digestive enzyme substrates on triglycerides?
    gastric lipase
  123. what digestive enzyme substrates on nucleic acid?
  124. how is pancreatic secretion regulated?
    pancreatic secretion is regulated by sphincter or oddi
  125. true or false?

    digestive enzymes  in the pancreas are released in an active form?

    pancreatic enzymes are released in an inactive form so they don't digest the pancreas
  126. what are brush border enzymes?
    brush border enzymes are digestive enzymes located at the surface of microvilli
  127. what macromolecules do brush border border enzymes break down?
  128. what are the 2 mixing and mechanical digestion that occurs in the small intestine?
    • 1-segmentations 
    • 2-migrating motility complexes
  129. what is the stage of each of the 4 macromolecules when they are absorbed into the cells?
    1-monosaccharides are simple sugars

    2-amino acids stay amino acids

    3-triglycerides are small/large chains of fatty acids

    4-nucleotides are nucleic acids
  130. what happens to lipids in the small intestine?
    they are broken down to monoglycerides
  131. what does your body in terms of carbs, proteins, triglycerides and nucleic acid absorpb?
    • carbs=glucose
    • proteins=amino acids
    • triglycerides=monosaccharide
    • nucleic acids=nucleotides
  132. which molecules are actively absorbed?
    glucose, galactose, amino acids, di and tripeptides
  133. which molecules are absorbed by diffusion?
    fructose, short and long chain fatty acids
  134. how is water absorbed?
    via osmosis
  135. what components of diet helps your body absorb water?
    electrolytes, monosaccharides and amino acids
  136. how are electrolytes and amino acids absorbed?
    via active transport mechanisms?
  137. what are the two types of movement in the large intestine?
    • 1-gastroileal reflex
    • 2-mass peritalsis
  138. does the large intestine secrete any enzymes?
  139. what type of chemical digestion takes place in the large intestine?
    bacterial conversion
  140. what important component of your diet is absorbed in the large intestine?
    vitamin B and K
  141. when does chyme become feces?
    3-10 hours when chyme has become solid or semisolid